Anthony Browne, Europe Correspondent of The Times, examines the background to the debate on future migration from the European Union:

Why did the UK open its doors to Eastern European workers when other EU countries imposed restrictions?

Self-employed people from Eastern Europe can work anywhere in the EU but the UK, Ireland and Sweden were the only EU countries to give other migrant workers an automatic right to work there. The rest imposed a restricted, transition period of up to seven years. Ministers in the UK said it needed workers to fill gaps in the labour market but countries like France and Germany have higher rates of unemployment and were concerned that their nationals could lose out.

When do Romania and Bulgaria join the EU?

The two former Soviet Bloc countries are almost certain to be given the go-ahead to join on January 1 2007 at a meeting next month. There is a slight chance that date could slip to 2008 because of concerns about whether they are ready to join, but that would be difficult politically.

What rights will the Romanians and Bulgarians have when they join?

They get an automatic right to visa-free travel - at present there is a strict visa regime - and they get the right to live anywhere in the EU. But they don't get an automatic right to work or claim benefits because all EU countries are allowed to introduce a transition period of up to seven years - as most countries did when Poland and seven other eastern European countries joined on May 1 2004.

So which countries are going to impose restrictions on Bulgaria and Romania?

It is likely that countries such as Germany, France, Italy and Austria will impose restrictions. And now pressure is growing in the UK and Ireland for restrictions.

In the UK, who wants restrictions on workers form Bulgaria and Romania?

Almost everybody - the Conservatives, the Confederation of British Industry, British Chambers of Commerce and now Blairite former ministers like John Denham and Frank Field. Charles Clarke, the former Home Secretary, had suggested there would be no restrictions but the Government's mood has changed and ministers are now hinting that it may impose restrictions. John Reid, the Home Secretary, is more populist than his predecessor and is more likely to impose limits, especially since Government estimates of the number of migrant workers from eastern Europe were woefully low.

What are people worried about?

Poland and the seven other eastern European countries that joined in 2004 are poorer than most of western Europe but Bulgaria and Romania are poorer still; unemployment rates are very high and rates of pay are low. Critics are therefore concerned that there could be somewhere between 50,000 to 300,000 Bulgarian and Romanian workers coming to Britain in search of work next year, putting an undue strain on public services.

What is the reaction in Bulgaria and Romania?

There has been a lot of anger in the press in Bulgaria and Romania that one of the prime benefits of joining the EU - the automatic right to work anywhere - will be restricted. Even previously friendly Ireland is now likely to impose restrictions. It's a big political issue there and the trade unions are campaigning for the re-introduction of work permits for workers from Eastern Europe.

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