The FSA has hit out at a number of the "bigger" lenders over their concerns about verifying income for the self-employed or those with irregular earnings.
Mortgage policy manager Lynda Blackwell said the regulator is being told validating these applicants is going to be "too difficult".
Speaking at the Building Societies Association (BSA) annual mortgage seminar this week, Blackwell added some lenders would "rather pull out than service the less straightforward consumer".
She said the self-employed and those with irregular income can still prove how much they earn - it may just take them a little longer to get a mortgage.
"Some of the bigger firms have told us that making a basic lending decision about affordability in these cases is going to be too difficult and risky and therefore they'd rather pull out than service the less-straightforward consumer.
"So they were happy to self-certify - but not assess affordability properly.
"We are asking you to do nothing more than make a realistic assessment on the facts before you in each case. If verifying income makes you think the lending is risky, isn't that worth knowing?"
Blackwell said a consultatio paper on these issues would be out in November.
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