Bangkok’s Suvarnabhumi international airport was today a scene of abandoned chaos. Check-in counters were closed. Shutters were pulled down. Stranded passengers lay akimbo on the floor, asleep on baggage trays, slumped on check-in counters, leaning bewildered in front of the electronic flights board which showed a list of “cancelled”, “cancelled”, “cancelled”.

Outside, the sweeping approach roads to the airport were blocked with coiled razor wire and miles of parked firetrucks and cars. A thousands-strong crowd of anti-government militants thronged the airport forecourt, shouting, clapping and generally expressing their determination to hold the terminal until the Thai government resigns.

It’s a bold gamble. With six per cent of Thailand’s gross domestic product directly dependent on tourism the government cannot afford a long-term paralysis of the nation’s most important hub - an airport which processes 40 million passengers a year. Many experts predict a violent counter-invasion is on the cards.

But it won’t be easy to dislodge the militants. The sweeping approaches to the new US$ 4 billion airport were comprehensively blocked with parked cars, fire-trucks, tethered trolleys and coiled razor wire. Inside the terminal, forlorn notices tacked to deserted counters told the story. “We regrettably inform that this Bangkok Airport is now closed,” said a note posted to the JAL counter.

Roy Manning, an electronics engineer from Cambridge, was seething. “I got here at 10.45 last night from Phuket,” he said. “They’ve kept us waiting since then, they didn’t tell us anything. There was no food this morning. Last night there was a little bit going around, but it was totally unorganised."

Mr Manning had seen the anti-government militants of the People’s Alliance for Democracy (PAD) circulating through the crowds of stranded passengers, offering bottles of water and snacks. He is uninterested in their rationale. “I knew this was happening some time ago,” he said. “But I thought it was all over.”

One Thai Airlines official estimated that between 2000 and 3000 Thai Airlines passengers were stranded in the transit sections of the airport today before officials began trying to move them out to hotels. Mr Manning said he was reluctant to leave without further information concerning his onward flights, but he was warned the water and power in parts of the terminal would be turned off.

Annette Larsson, from Stockholm, was concerned about her 82-year-old mother-in-law, slumped exhausted on a lounge after spending the night in a wheelchair.

David Withey and his wife Pam, from York, were caught at Suvarnabhumi on Monday night on their way from Perth to London. They had been flying business class – a special luxury for their retirement holiday – and they found themselves sleeping on the floor of the business lounge.

“And to think we paid a lot of money for this,” Mr Withey said. Mrs Withey said she could hardly stand up this morning her bones were so stiff.

A PAD-controlled website this morning claimed special operations police at the airport began firing on them at 6am, injuring two protesters and potentially setting off a violent confrontation.

The PAD militants also reported a bomb exploding at the airport early this morning, injuring one protester. The website also claimed the police shot at a six-wheeled truck transporting “necessities” to the PAD militants at the airport.

The PAD protesters began their final push to topple the Thai government on Monday. “The final rally is well into its 50th hour and the supporters of the PAD have been pressuring the traitorous government to step down with peaceful means,” the PAD reported on its website.

“Armed with only the plastic hand clappers, the PAD protesters have marched to various key locations including Parliament, Finance Ministry, the Metropolitan Police Bureau and the Government’s temporary seat at Don Muang Airport. However, to no avail, the proxy Government has failed to show any sign of remorse or any intention to step down as demanded by the PAD. In addition, it continues to cling on to power and is determined to amend the charter for the interests of its puppet master and his associates.

“The People’s Alliance for Democracy is left with no choice but to step up its peaceful rally by blocking off access to the Suvarnabhumi Airport. This is considered to be an ultimatum for (prime minister) Somchai Wongsawat and the Cabinet to resign immediately and without any condition.”

The ultimatum went to apologise for any inconvenience to the public and international visitors. “But the PAD believes the measure is crucial to bring an end to the traitorous-killer government.”

The militants called on the public to join the PAD movement to “restore morals to Thai society”. General Anupong Paojinda, the army chief, has said there would be no coup, even if violence broke out. “The armed forces have agreed that a coup cannot solve our country’s problems and we will try to weather the current situation and pass this critical time,” General Anupong told reporters in Bangkok.

For its part, the government, led by prime minister Somchai Wongsawat, has refused to quit, insisting that the overwhelming mandate it won in elections held at the end of last year stands. Mr Somchai is the brother-in-law of ousted and exiled former Thai prime minister Thaksin Shinawatra, a telecommunications billionaire who is reviled by the militants as corrupt and a puppeteer who still controls Thailand from abroad.

Times Recommends

• Rio Tinto four held as China prepares case
• Diplomats must keep heads down and trousers up
• When in Rome should one make like Berlusconi?