ALASTAIR DALTON TRANSPORT CORRESPONDENT (adalton@scotsman.com)

PASSENGERS face disruption this summer from extra security measures at airports, railway stations and ferry terminals as transport bodies seek to reassure travelers.

The moves came as a security expert urged screening to be considered for events at next month's Edinburgh Festival if the terrorist threat level remains critical.

The latest measures include steel bollards being ordered to protect stations on Glasgow's Subway system, while there will be increased security at major events, such as the T in the Park music festival near Kinross this weekend.

Strathclyde Partnership for Transport, which runs Glasgow's Subway, said it was accelerating plans for bollards, and patrols by British Transport Police had been stepped up. Armed officers from Lothian and Borders and Strathclyde Police were patrolling major stations in Edinburgh and Glasgow as part of sweeps of the city centres.

Car parks inside Edinburgh Waverley and Glasgow Central stations have been closed, while parking has been restricted around Caledonian MacBrayne's west coast ferry terminals. Concrete blocks have been installed outside Aberdeen ferry terminal. Security around the Queen has also been visibly increased, with a heavy police presence during her visit to Dundee University yesterday. This is likely to be repeated for other royal engagements in Scotland this week, including tomorrow's garden party at the Palace of Holyroodhouse in Edinburgh.

Professor Paul Wilkinson, who chairs the advisory board of the Centre for the Study of Terrorism and Political Violence at St Andrews University, said searching people and bags as they entered venues would be a key measure if threat levels remained at their highest during the Edinburgh Festival.

But he admitted such measures would not be feasible for events such as T in the Park. Organisers are expecting 80,000 people a day at the event, while there will be some 200,000 at Fringe Sunday in the Meadows during the Festival, and even more at the Bank of Scotland Fireworks Concert in and around Princes Street Gardens.

Prof Wilkinson said security at such events would rely on the vigilance of organisers, those attending and staff and stewards. He added: "Good liaison with the police is essential. We know the al-Qaeda network is keen to target public gathering places and it has absolutely no compunction about doing so."

Chief Constable Colin McKerracher, of Grampian Police, who is president of the Association of Chief Police Officers in Scotland, said: "Any event where there are a lot of members of the public, we will obviously up police presence there and just make sure that security is enhanced."

EXTRA shielding for airport terminals may be required following Saturday's attack, Scotland's leading police chief admitted yesterday.

Colin McKerracher, the president of the Association of Chief Police Officers in Scotland, said that such buildings may require additional protection, such as security fencing.

The Chief Constable of Grampian Police said: "I think the physical fronts of airports in Scotland will probably be changed after this." Mr McKerracher said the restrictions on vehicles outside terminal buildings might have to continue for weeks or months, but he did not think they would be permanent.

BAA, which runs Glasgow Airport, has said it complied fully with government specifications for building security, but would await any security review.

Police officers were yesterday making a fingertip search of the area around where the blazing Jeep Cherokee was driven into the main terminal at the airport.

The Jeep was taken away by lorry for further examination on Sunday.

However, from damage which was still visible yesterday, it appeared that the vehicle had been driven at one of two adjoining sets of double doors at the west end of the terminal frontage. These appeared to have been too narrow for the vehicle to have fitted through.

The remains of an illuminated advertising board which the car may have struck was visible between the two sets of doors.

There are metal-covered pillars on either side of the doors, which protrude slightly on to the pavement, but security experts doubted whether extra physical measures would have much effect.

Chris Yates, an aviation security analyst for Jane's Airport Review, expressed scepticism over the proposals. "People will always find some way of striking at terminal buildings," he said.

"They have stood the test of time, and I'm not sure if we need to redesign them.

"You could spend a fortune on putting extra measures in place, but the sort of people involved in such attacks know how the system works and how to circumvent it."

BAA said restrictions on the forecourts of all seven of its UK airports, which also include Edinburgh, Aberdeen, Heathrow and Stansted, remained in place.

A spokesman urged passengers to travel by bus or taxi rather than car and allow extra time for their journeys.

Passengers were forced yesterday to walk from drop-off points to the west and south of the main terminal, but the airport's car parks were reopened.

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STEPHEN MCGINTY - Scotsman.com News

AS THE green Jeep Cherokee swept through the roundabout at Glasgow Airport and approached the terminal building, its two occupants steeled themselves for an apocalypse.

The driver was dressed in a blue boiler suit with black plastic bags tied around his feet. His partner, in the front passenger seat, wore a dirty, grey T-shirt and sand-coloured cargo trousers. It was the first day of the summer holidays, yet these men were not tourists.

Scotland's long innocence to acts of political violence was to be shattered. At 3:15pm on Saturday, on a day when an estimated 35,000 passengers were due to pass through Scotland's busiest airport, the Jeep sped along a road restricted to taxis, suddenly veered right and then, just as swiftly, the driver spun the wheel hard left.

The Jeep passed between the protective steel bollards and smashed into the front of the main doors of Terminal 1, scattering stunned passers-by.

The vehicle's wheels were jammed under an advertising board and witnesses rushed to assist what they believed to have been an accident.

So charitable a notion was quickly corrected by the driver, who, witnesses said, poured out petrol which set the front of the car alight. Climbing out of the car, he was quickly engulfed in flames, yet he still struggled to the boot where several gas canisters are believed to have been stored. As one witness said: "It was amazing how calm he appeared."

As the driver, a massive man, described as over 6ft tall with a broad build, struggled with the boot, Stephen Clarkson, an off-duty police officer, snatched up a fire extinguisher and tried to put out the flames. The man turned and is alleged to have screamed: "It's a bomb. It's a bomb."

A confused struggle then took place with police officers who arrived and squirted CS spray into the driver's face.

Meanwhile, witnesses said the Jeep's passenger tried to run into the terminal with canisters of gas or petrol, before being tackled by security guards, police and members of the public.

Airport staff began spraying the car with a fire extinguisher but were forced back when it exploded. At 3:16pm, the two men were dragged out on to the central reservation as the fire alarm began to sound and a mass evacuation of the airport began.

As passengers streamed out of the terminal, they passed - and some filmed - the driver, his clothes incinerated and his partially naked body badly burned. One shouted: "Let him burn."

The Jeep's passenger, meanwhile, had his hands cuffed behind his back and was led off to a police van.

THE airport's major incident planning procedures were swiftly launched. The airport was shut down. Air traffic controllers began contacting flights en route and steered them away to alternative terminals, including Edinburgh, Prestwick and Newcastle. Those planes already queuing on the runway were instructed to wait - a long afternoon and evening had begun. On board, some passengers switched on their mobile phones and downloaded images of the blazing car.

The first of 16 fire engines arrived at Glasgow Airport by 3:23pm, followed shortly after wards by a major incident control unit, a large articulated truck from which the work of dozens of staff was co-ordinated. The blazing car had ignited part of the roof of the terminal building, and it and the Jeep were bombarded with thousands of gallons of water from high-pressure hoses.

The news of a suspected terrorist attack at the airport began to cascade down through Strathclyde Police to the anti-terrorism branch of the Metropolitan Police, who were already investigating the two car bombs discovered in London early on Friday.

Peter Clarke, the calm and bespectacled head of the anti-terrorism branch, immediately dispatched officers to Glasgow. He would soon follow.

The response of Strathclyde Police was to gear up its elite firearms squad and dispatch an increased number of foot patrols to Pollokshields, where many of Scotland's Muslim community reside.

Alex Salmond, the First Minister, was showing a constituency guest around his official residence, Bute House, when the news was broken to him by a civil servant shortly after 3:30pm.

The official opening of the Scottish Parliament by the Queen had finished just three hours earlier. He was looking forward to an evening at the theatre with his wife, as well as his invited guest, Sir Sean Connery.

Mr Salmond immediately ordered that the Scottish Executive emergency room, located in the basement of St Andrew's House, be prepared and began a round of meetings on the matter.

At 5pm, shortly after the room - which contains extensive communication facilities and video conferencing equipment - was ready, Mr Salmond had a short conversation with Gordon Brown, the Prime Minister. All previous antagonism was put behind them as both men discussed the threat to the United Kingdom. It was agreed that they would speak again at the next meeting of COBRA, scheduled for 7:30pm.

In Glasgow, at about this time, the threat appeared to have heightened. The driver of the Jeep Cherokee, who had been extensively burned, had been taken to the Royal Alexandra Hospital in Paisley. He was admitted to the accident and emergency department, accompanied by police officers armed with sub-machineguns.

At about 5:30pm, the entire unit was swiftly evacuated as hospital staff, after removing the suspect's clothes, discovered what they believed to be a suicide belt. Fearful that the device could detonate in the ward, police officers picked it up and sprinted to the nearest open ground - the Ferguslie Cricket Club.

Angela Docherty, a minibus driver, saw a man run down the hill carrying an object. He shouted: "Run for your f****** life." When the bomb squad arrived, they found it was not an explosive device.

The COBRA meeting in London took place at about 8pm, and the First Minister, along with the justice minister, Kenny MacAskill, and the Lord Advocate, Elish Angiolini, contributed via video-conference.

Mr Salmond then gave a press conference at St Andrew's House, before setting an example to the public and continuing with his earlier plan to join his guests at a production of the celebrated play, Black Watch.

The seat beside Sir Sean in a gym hall at Edinburgh University's Pleasance complex was empty during the performance, but the First Minister arrived afterwards. It was a lead the people of Glasgow were only too glad to follow. The city centre was packed with people able to find humour in the heightened police presence. At just before 11pm, the Tunnel nightclub was ringed with police officers in helmets and sub-machineguns, after a false alarm over a suspect package. One young man walked past and said: "Christ, the bouncers are heavy tonight."

The evening was not so much fun for those passengers who, after as long as five hours on a plane, were billeted to the Scottish Exhibition and Conference Centre (SECC) to spend the night, before alternative travel arrangements could be made in the morning.

THERE was to be no sleep for senior officers of Strathclyde Police and the Met's anti-terrorist branch who were fielding calls at a rate of 100 per hour.

Aware of strong links between the attempted bombing of Glasgow Airport and the London bombs, Mr Clarke flew north to ensure there was proper co-ordination between forces.

The eerie twilight of a mid-summer night would see a number of clandestine police operations across Britain. At about midnight, Met officers, along with the West Midlands counter-terrorism unit, would use unmarked cars to tail two suspects along the M6, before forcing them to stop near Sandbach, Cheshire.

At 5am, the quiet of a suburban street in Renfrewshire was rocked by the presence of armed police. Ian Thomson, 25, a navy serviceman who recently returned from Afghanistan, watched the drama unfold from his mother and father's livingroom window, directly across from 6 Neuk Crescent in Houston, where the suspects are believed to have resided.

He said: "I was sleeping on the couch and I got woken by my mum at 5am, who said, 'You better look at this'. The road was closed off by uniformed police officers and there were several police cars parked outside. There were about 14 armed police officers, and another half-dozen uniformed police.

"A couple of guys covered the front and about eight armed police went round the back. I heard them trying to strike the door down, although I couldn't see them go in."

The owner of the house, Myra Mills, turned on the television a few hours later to see police officers going in and out. In April, she had rented the house, through Let It, one of Scotland's largest residential letting agencies, to what she was told was a young Asian doctor, possibly with the name Mohammed.

THE iconic image of contemporary fear - police in boiler suits investigating alleged terrorist suspects in a quiet, residential street, so familiar to England - had, with weary inevitability, come to Scotland. The greatest fear of the Muslim community, that the suspects were Scots, appeared, however, to be unfounded.

Mr MacAskill yesterday insisted they were not. That news came as a major relief to all of Scotland's imams, who gathered at the Central Mosque in Glasgow to discuss a suitable response, with Mohammed Sarwar, the Glasgow Central Labour MP, and Bashir Maan, the Muslim community leader.

They were supported by the First Minister, who joined them at their meeting just after 3pm. Mr Salmond had first visited Glasgow Airport, where the first flight since the attack had taken off at 9am and which, despite massive queues, reopened less than 24 hours after the initial incident.

But the spectre of terrorism reared its head once again yesterday afternoon when, at 1:30pm, police carried out a controlled explosion on a white BMW in the car park of the Royal Alexandra Hospital. No bomb was found inside.

Last night, the citizens of Glasgow put a brave face on their airport's promotion to terrorist target. Mocking the apparent ineptitude of the suspects, one woman said: "Terrorists? Numpties, more like."

UNTIL yesterday, the most trouble Myra Mills has been caused by one of her tenants at 6 Neuk Crescent was a complaint about a soiled carpet that needed replaced.

Now, she finds herself an innocent party at the centre of an alleged terrorist cell operating from her house.

"Of all the houses in Houston they had to choose mine. It's frightening," she said.

Mrs Mills first learned of her new tenant through a phone call one afternoon in the middle of April. The caller was Colin Roe, a director at Let It, one Scotland's largest residential letting agencies, based in the Renfrewshire town of Paisley.

As the owner of the semi-detached house in Neuk Crescent in the village of Houston since the early 1990s, she had dealt with Mr Roe regularly over the years, as old tenants left and new ones arrived.

At the time of the telephone call, the house had been vacant for a couple of weeks.

Asking Mr Roe about her prospective tenant, Mrs Mills recalled the answer: "Colin said someone was interested in moving in. I asked what the person was like. Colin said, 'He's a young Asian man from down south. He's a doctor.'"

And so the new tenant moved in. For £550 a month, he received a fully furnished house, with two double bedrooms and a garage.

It was not until yesterday, as Mrs Mills sat watching the television news with her 96-year-old mother in her home in the nearby village of Kilmacolm, that she realised the problems her new tenant would cause.

"I was watching the screen, and knew they were in Neuk Crescent. When I realised it was my house, with the police all around it, I shouted 'Oh my God'. I was horrified, really frightened."

She added: "We've owned the house since the early 1990s. In all that time we've been letting it out, there's been no hassle."

No-one from Let It was available for comment yesterday.

• MUSLIM and Asian community leaders yesterday condemned the attack on Glasgow Airport, saying all Scots must stand together to fight terrorism.

About 100 people, including religious leaders and community elders, gathered at Glasgow's Central Mosque, joined by Alex Salmond, the First Minister, and there was visible relief as it was confirmed by police that the suspects were not Scottish.

Bashir Mann, chairman of Glasgow Central Mosque, said: "The Muslim and Asian communities condemn such acts. This is evil and evil must be eradicated."

Mohammad Sarwar, the Glasgow Central Labour MP, said the criminals behind the attacks must not be allowed to damage good relations between Asian and non-Asian Scots. "These people don't care who they kill, whether they are Muslim or non-Muslim," he said.

• Des Browne, the Scottish Secretary, yesterday dismissed as "speculation" the possibility Glasgow Airport had been targeted because a Scot, Gordon Brown, had become PM.