The poll of mortgages brokers by specialist lender Paragon found three-quarters of advisers felt mortgages for the self-employed were the most difficult to find.

Retired customers also proved problematic with 52% of brokers finding it difficult to find suitable finance for these customers. More than half of advisers (51%) said customers who had complex sources of income were also increasingly difficult.

Almost a year on from the introduction of the Mortgage Market Review (MMR) rules, 43% of brokers said there had been no change to their business.

However, a quarter of respondents said they had seen lower levels of business, suggesting more customers are heading directly to banks and building societies.

A year on from the new regulations, some 15% of brokers said they were still unsure what its long-term impact would be on the market.

John Heron, director of Paragon Mortgages, said: “The research from the first quarter is really interesting. What it shows is there is still some uncertainty in the market about the long-term impact the MMR changes will have on business volumes.

This isn’t unexpected, as with any significant change in regulation there will always be a period of adjustment, but it is important the industry monitors this carefully.

“We need to recognise that there is no such thing as the average mortgage customer anymore, people have a greater variety of circumstances and we need to be more innovative in order to meet increasingly varied demand from customers.”