Flights costing less than £10 will help to bring tens of thousands of new migrants to Britain, it can be revealed. Budget airlines are opening new routes to cater for waves of workers from Romania and Bulgaria when they join the European Union.

The migrants will get set to leave their homelands for a brighter future in Britain and other rich western countries as the European Commission today gives the green light for the planned EU expansion on January 1, dismissing demands to delay entry for another 12 months.

The development puts Labour under fresh pressure to act now and shut the door to the thousands of migrants. Last week Home Secretary John Reid gave the strongest hint yet that the Government is ready to bow to public pressure and control the next wave of immigration.

But, given such cheap, rapid means of mass movement, fulfilling this policy may well prove beyond the Home Office. Low-cost airline Wizzair is beginning a three-times-a-weekservice between Bucharest and London in January with tickets selling for just £7.75. Government taxes bring the total to £24.95.

Yesterday a spokeswoman for the airline told the Daily Express: "We think it will be a popular route when Romania joins the EU. We have already sold lots of tickets. "It will be very attractive for people who will want to go to Britain to work."

The company’s 180-seat capacity Airbus A320 will carry more than 500 passengers from Romania to Britain every week.

Last night Sir Andrew Green, chairman of Migrationwatch UK, said the new route would prove highly significant. He said: "Low-cost flights have played a huge role in the massive immigration from Poland.

"They could do the same for Romania and Bulgaria which are even poorer countries."

Speaking from the company’s offices in Bucharest, the Wizzair spokeswoman added: "We are also opening up other routes in January to Germany, Hungary, Spain and Italy. These are also for people who want to work or visit these countries after we join the EU."

Wizzair already operates a four-times-a-week service from the Bulgarian capital, Sofia, to London with tickets selling for £1.

But the high demand for seats in January means that the airline has almost sold out. A spokesman from Wizzair’s Sofia office said: "You can buy a ticket to London for as little as £1 for the period of November or December.

"But in January the route is already very popular. Almost all of the tickets have been sold. We only have a few seats left for the beginning of the month. The best price in January is £5. That is for January 22."

The European Commission progress report on Bulgaria and Romania, the last obstacle to membership, will today give the go-ahead for them to join the EU in January.

The confirmation comes despite continuing concerns over corruption and domestic conditions inside their borders.

Labour have faced demands from all quarters not to repeat the disaster of the last EU enlargement, when it threw open its doors to eight Eastern European countries, including Poland, in 2004.

Mr Blair predicted fewer than 13,000 a year would come, but at least 600,000 have arrived in the last two years.

Experts have warned that as many again could come from Romania and Bulgaria if we grant the same access, because they are poorer than their neighbours. Despite Mr Reid’s apparently firm line, the Home Office refused to be drawn on the issue yesterday.

The Conservatives, senior Labour MPs and business leaders, including the CBI and British Chambers of Commerce, have called for limits.

David Frost, Director-General of the BCC, said: "We need a pause after the huge influx from Poland and the significant impact it has had.

"The numbers that have come in have been way, way above Government projections. The Government needs to make a decision and the sooner the better."

Tory MP Andrew Rosindell feared that the increase in low-cost flights was a "worrying sign". He said: "It is a sign that the low-cost airlines are ready to benefit by potentially encouraging people to fly to Britain.

"The Government needs to think very carefully before they allow another avalanche of people turning up on our doorstep looking for work."