Tax return and the bank

[Russwhitehouse]

For some reason, the bank have recently asked to see copies of my French and UK tax returns. In thirteen years of living here they've never asked before and they haven't explained why they want to see them. I've never had any bother with the tax people either here or in UK and would have thought that my tax affairs are between me and the tax authorities and none of the banks business given they are a PLC (HSBC) and not a government body. Has some new rule emerged without my knowledge or anyone experienced the same? Do they have a right to see my returns or are they trying to have a nosey with some ulterior motive? Thoughts anyone?