Private landlords whose properties are affected by falling values may find their mortgage lenders demand extra equity, it has been claimed.

Chairman of the Residential Landlords Association Alan Ward said this may be the case if loan-to-value ratios need to be put back in line.

"If you borrow £500,000 on a 100 per cent mortgage and the value of property drops by 20 per cent, the lender can demand £100,000 from the borrower," he said.

Landlords at the moment are demanding steady and reliable tenants, Mr Ward suggested, as this can help guarantee a sustained income.

The FindaProperty.com Rental Index, from June 23rd, found that the average rental price increased in June for the first time since August 2008.

The average asking rent increased by 0.5 per cent to £823 per month in June compared to the previous month, although it is still 5.3 per cent lower than June 2008.

Rental yields remained stable at 4.56 per cent in June, with average yields at 4.33 per cent for houses and 5.24 per cent for flats.