The UK is experiencing the biggest immigration wave in its history thanks to the arrival of eastern European workers, says an expert.
Eastern Europeans: Huge demand from employers
A report by two of the country's leading migration academics says the number of foreign nationals working in the UK topped 1.5m in 2005.
Confirming figures already published, the study says the growth is down to an open labour market to new EU-workers.
Irish workers remain the clear leaders but their dominance is slipping.
The Economic and Social Research Council paper charts some of the key factors that will have a significant impact on the future shape of Britain is population.
It brings together official statistics and analysis by Professors John Salt of University College London and Phil Rees of Lees University, two highly respected migration experts.
Prof Salt has advised the Home Office on a number of key issues, including the difficulty in trying to count illegal migrants working in the black economy.
The report says that when 151,000 more people came to the UK in 2004 than left, it represented a major shift in the UK's migration patterns.
POLES AROUND UK
South East 13,820
South West 12,170
North West 9,830
North East 8,780
Source: Home Office
This change, said Prof Salt, was down to the UK's decision to open labour markets to workers from new European Union states.
Ten countries joined the European Union in May 2004, eight of them being the Eastern nations of the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Slovakia and Slovenia.
The UK, along with two other existing EU states, opened the jobs market to workers from the eight, saying it would help the economy grow.
Other EU nations have blocked those workers under transitional rules.
Prof Salt said: "Opening up of the labour market to citizens of the new member states of the EU initiated what is almost certainly the largest ever single wave of immigration the British Isles have ever experienced, with Poles the largest ever single national group of entrants."
Between May 2004 and March 2006, six out of 10 eastern European workers who registered in the UK were Polish, comprising 228,000 of the 375,000 recorded entries, according to official figures.
However, it is difficult to say how many of these workers are actually in the UK at any one time because of the way the figures are compiled.
The report concludes that based upon what we do know, central and eastern European workers now make up a tenth of the foreign-born labour force.
In contrast, while Irish workers have historically been the largest single group of foreign workers, their dominance has fallen dramatically - from 22% of all foreign workers in the UK in 2005, the proportion for 2005 was half that.