Around 1.3 million citizens from the eastern block of the European Union are living and working in the UK, a new study has revealed.

The Office for National Statistics (ONS) today (10 July) released its second report in a series on immigration, detailing how many eastern Europeans call the UK their home and how many British ex-pats are present in those countries.

The ONS analysed the so-called 'EU8' citizens and looks at how they have integrated into the UK workforce. The EU8 block comprises Poland, Lithuania, Czech Republic, Hungary, Slovakia, Slovenia, Estonia and Latvia.

Of the 1.3m, the majority play a significant role in the UK economy – over 80% are employed and young enough to contribute to the country's growth in forthcoming decades. They represent 3% of the overall UK workforce.

The largest group in the UK of EU8 citizens comes from Poland, who supply around 813,000 immigrants. The Polish community is the largest foreign-born population in the country, and would be the second largest city in Poland after Warsaw.

A full 40% of EU8 workers in the survey were over-qualified for the job they were doing, due to the impossibility of converting their home academic titles into a same-level UK one. Also, 38% of EU8 citizens were employed in non-specialised occupations such as distribution, hotels and restaurants and manufacturing.

The ONS also released data on UK citizens living in EU8 countries. More than 14,000 UK citizens live in these nations with over 40% of them residing in the Czech Republic, according to figures released by Eurostat.

6,000 citizens in EU8 nations have been claiming UK state pensions, according to Department of Work and Pensions.

The number of state pensions claims has rocketed in Poland: there were 2,926 pensions in 2016, twice the number compared to November 2010.

However, pension claimers are not necessarily British as the ONS specifies that "Anybody with qualifying National Insurance contributions and/or credits can receive the UK State Pension". Also that most of the UK-born citizens living in these countries are not in pension age.

This might be due to a flux of migrants returning to their own countries due to poverty and fears following the Brexit vote.