Prospective buy-to-let landlords have been advised to carefully research the local market before making any commitment to purchasing a property.

The comments from the Association of Residential Lettings Agents (Arla) come as the rental market shows no sign of slowing, with the organisation recently reporting that 57 per cent of landlords questioned in one of its studies intend to add to their property portfolio over the next 12 months.

"You've got to be careful when you make any investment," said Malcolm Harrison, a spokesman for Arla.

"You’ve got to check out what the local market is all about and what do they want.

"When you talk to letting agents they will tell you what's in demand and the kind of property that is most successful in buy-to-let investment in that particular area."

According to the latest buy-to-let index from Paragon Mortgages, rental incomes increased by an average of 2.2 per cent over the month of June and by 4.2 per cent over the last quarter.

In addition, the cost of an average rental property rose by three per cent between May and June, from £174,552 to £179,793.