Evangela Liogka and Christakis Philippou, both of west London, and Timothy Entwistle, of Dorset, denied five counts of conspiracy to defraud.

Peter Kemp, who managed the businesses, has pleaded guilty to the same charges.

Prosecutors alleged the group launched five agencies in London, taking in huge bookings before collapsing the firms and leaving customers empty-handed.

'Cut price' deals

Prosecutor Martin Edmunds QC said Mr Philippou, 64, of Bark Place, Bayswater, was at the "centre of the action".

Ms Liogka, 40, from Montpelier Place, Knightsbridge, was "effectively overseeing" the agencies' call centres, the court heard.

Mr Entwistle, 57, from Ludworth in Dorset, is a trained accountant and handled the financial aspects of the business and helped start the companies, Mr Edmunds said.

The firms, which operated online and through Teletext, would advertise "cut price and very attractive deals" to customers, the prosecutor said.

There were thousands of disappointed customers Martin Edmunds QC, prosecutor

The "deliberate frauds" ran seasonally between July 2003 and August 2006, he told the court.

"They would get bookings coming in thick and fast at the height of the season and then the company would fail, and the bulk of customers would not get their holidays.

"These businesses, between them, took millions of pounds. There were thousands of disappointed customers," he said.

The five companies allegedly involved were Ciao Travel Ltd, Onshine Ltd, Grayrise Associates Ltd, Orange Sun Ltd and Sun Orient Ltd.

The money earned through customer bookings by two of these firms allegedly ended up in bank accounts in Cyprus, Greece and Spain, the court heard.

The trial is expected to continue for eight weeks.