Here is a recent response I received from the DWP which may help.
A8 nationals who are working legally in the UK are able to claim HB/CTB and in some cases JSA(IB) because they are treated as being qualified persons under the Immigration (EEA) Regulations 2006. Working legally is defined in regulations as employment registered with the Worker Registration Scheme. They are required to produce their WRS card and certificate to confirm that they are working legally. However, if they cease working before completing 12 months continuous employment they lose their right to reside and their worker status, so are no longer entitled to benefit because work / jobseekers from A8 countries are required to be self-sufficient while they look for work (prior to gaining EEA worker status).
Once an A8 national has completed 12 months continuous employment as a registered worker they gain full EEA worker status/rights and can claim HB /CTB if they lose their employment as long as they remain in the labour market and are in receipt of JSA(IB).
A8 nationals who are working in a self-employed capacity are also allowed to claim HB/CTB whilst working and must produce evidence of their self-employment such as audited accounts or any documents issued by HMRC in respect of self-employment such as a CIS card. An A8 national who ceases self-employment doesn’t gain worker status even if they have worked continuously for 12 months; they would need to work as a registered worker for 12 months to gain EEA worker status.
Please also note that Poland, along with the other accession countries, is now an EEA country so it’s nationals are not subject to immigration control so are not required to apply for permission to enter the UK.
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