The landscape was already looking pretty tough for buy-to-let investors. But advisers fear the unexpected profits warning from Bradford & Bingley this week could make life even harder.

The UK's biggest buy-to-let lender said rising mortgage arrears would trigger losses of around £8m in the first four months of this year. It was forced to renegotiate its planned £300m rights issue and sell a 23 per cent stake of its business to TPG, the private equity investor.