Migrationwatch UK states that in the third quarter of last year there were 600,000 more workers in the UK from eight former Soviet bloc countries than in 2004, when they became members of the EU.

Over this same period, UK youth unemployment increased by around 450,000.

According to information from the Office for National Statistics (ONS), UK youth unemployment rose from 575,000 in the first quarter of 2004, to 1,016,000 in the third quarter of 2011. Over this same period, the number of workers from A8 countries joining the EU that year (Poland, the Czech Republic, Hungary, Slovakia, Slovenia, Estonia, Latvia and Lithuania), rose by 600,000.

Migrationwatch UK, campaigning for stricter policies on immigration, stated it would be "a very remarkable coincidence if there was no link at all" between the figures.

Chairman of the organisation, Sir Andrew Green, said, "Correlation is not, of course, proof of causation but, given the positive employability characteristics and relative youth of migrants from these countries, it is implausible and counter-intuitive to conclude - as the previous government and some economists have done - that A8 migration has had virtually no impact on UK youth unemployment in this period.

"We hear a great deal from employers about the value of immigrant labour, especially from Eastern Europe, but there are also costs some of which have undoubtedly fallen on young British born workers”.

Migrants from the A8 countries "have tended to be disproportionately young, well-educated, prepared to work for low wages and imbued with a strong work ethic", Sir Andrew said.

However, Matt Cavanagh, associate director at the left-leaning IPPR think tank, said that the report was “just conjecture, disingenuously presented as research”, and according to them youth unemployment was rising before the Eastern Europe influx.

"To try to make our youth unemployment problem look like it is only or mainly an immigration problem - as this report does, by selective use of dates, and a methodologically bogus juxtaposition of aggregate A8 migration with aggregate rise in unemployment - is a profound mistake, and an irresponsible one at that," Mr Cavanagh said.

“There are a number of established statistical methods for testing the robustness of any apparent correlation - but this report doesn't even bother to try”, he added.

A recent ONS report looked at trends in Eastern Europe migration and stated that just over 300,000 workers arrived in the UK during the recession. It also stated that there was a “growing body of evidence” that A8 workers were filling posts that local employers find it difficult to fill with domestic workers.

"It is not only an issue of migrants accepting the dirty, difficult and dangerous jobs that the UK labour force shuns, but also a matter of the very positive work ethic amongst A8 workers”, the report said.

The Home Office has said it is working to reduce net migration.

"Controlled migration can bring benefits to the UK economy, but uncontrolled immigration can put pressure on public services, infrastructure and community relations," a spokesman said.

"That is why we are ensuring graduates and the workforce get the opportunities and skills they need so that they can find work, and why we have maintained restrictions on workers from Romania and Bulgaria, and made it clear we will always introduce transitional controls on new European Union member states to stop unregulated access to British jobs."