What proof does an EU citizen need for a UK mortgage?

Q I work with a Slovak woman who is trying to get a mortgage with Halifax. Despite Slovakia's membership of the EU, Halifax still want a visa before it will agree to the mortgage. She's pulling her hair out. Can you offer any help or advice?
DT

A Halifax simply wants to know that she is who she says she is and that she is allowed to work here, in the same way that a UK citizen would be asked for proof of identity and employment status when applying for a mortgage.

But assuming that your colleague came to the UK after May 1 2004 (or started a new job in the UK after then), it is a bit odd that the Halifax is asking for a visa. What they should be asking for, according to the person I spoke to at the Halifax, is a copy of her workers' registration certificate or her EEA residence permit. The permit can be applied for after 12 months' uninterrupted employment in the UK.

More information on the worker registration scheme for citizens of the EU accession states is available from the Home Office.