From April to June, workers from the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Slovakia and Slovenia increased by 44,000 compared to the same period in 2015.
Official figures showed there were now a total of 2.23 mln EU workers in Britain, and their number has grown by 238,000 people compared to the second quarter of last year.
UK unemployment fell by 52,000 to 1.64 mln during the same three-month period.
These figures are the first to be issued since June's EU referendum, when the UK voted to leave the European Union.
The labor market data showed the number of workers from the eight eastern European countries was nearly four times the level recorded 10 years ago.
It also showed there were 266,000 Bulgarians and Romanians in employment in the UK - a rise of around 87,000 compared with the second quarter of 2015. Citizens from the two countries have been able to work without restrictions across the EU since January 2014.
There were an estimated 944,000 employees from the remaining EU member states.
Overall, between April and June there were 2.23 mln EU nationals working in the UK - an increase of 238,000 year-on-year.
The number of workers from outside the EU remained nearly unchanged, at about 1.21 mln.
Lord Green, chairman of Migration Watch, said the figures represented "a milestone". "The pressures that this massive migration has placed on local communities go a long way to explaining the outcome of the referendum. The new statistics underline why it is essential not just to regain control of our borders but also to reduce net migration significantly," he added.
