Much more damage, however, is being done to Thailand's reputation, experts say.

The two-year-old Suvarnabhumi Airport, with ambitions of being a premier regional aviation hub, is the 18th largest in the world in terms of passenger traffic and the main gateway to Thailand for tourists and businessmen.

But aviation analyst Shukor Yusof at Standard & Poor's Equity Research noted that the airport had been plagued by various problems from Day One, and called the mob takeover 'the nail in the coffin'.

'It's shocking that thousands of people can just descend on the airport and shut it down,' he said.

News agencies reported last night that a Bangkok court had granted the airport operator an injunction to evict the protesters, but there was no indication that this would have any effect.

The takeover has put Thailand's hugely successful tourism industry in jeopardy as the high season approaches.

'This is very bleak news for the economy,' said Barclays Capital economist Leong Wai Ho, noting that the crisis was occurring against the backdrop of the global slowdown. 'It's going to cause dislocation in traffic and disrupt cargo flows.'

Several countries - Singapore, China, France, New Zealand and the United States, among them - have warned citizens to avoid travelling to Bangkok, or to act with caution if already in Thailand.

At Suvarnabhumi yesterday, many travellers, weary from the waiting and without food or drink, sprawled atop heaps of luggage and some said they regretted making the trip.

British retiree Jean McCartan told the Agence France-Presse news agency: 'We all came to Thailand because we love Thailand, but this has left a very bad feeling.'

Though some tourists were being let out, a quick check of the departure schedule at the airport's website told of the long haul ahead for them.

British Airways Flight BA 9 to Sydney: Cancelled. Thai Airways Flight TG 630 to Hong Kong: Cancelled. Cathay Pacific Flight CX 751 to Mumbai: Cancelled.

The unhappiness extended well beyond those stuck in Thailand. Thousands planning year-end trips there have been forced to make alternative plans.

At Changi Airport, hundreds turned up, many with children in tow, only to find all flights to Bangkok, whether by Singapore Airlines, Thai Airways, Jetstar Asia or others, cancelled.

Similar scenes played out elsewhere, as airlines from several countries worldwide, including Japan, Spain and Germany, cancelled flights.

Mrs Connie Cheong, 51, who had planned to leave for Bangkok yesterday with her husband and two teenage daughters, opted for a refund on her tickets when told flights to Bangkok from Changi Airport were off.

The administrative officer said the family would take a coach to Kuala Lumpur instead.

'We are disappointed of course, but it's good we got the travel refund. If the flight was still on, I think we would still have gone ahead,' said Mrs Cheong.

'I think the shopping area is quite safe.'

Additional reporting by Karamjit Kaur and Robin Chan.