As property prices have fallen, landlords have increased their property portfolios in the past year, according to research from the Association of Residential Letting Agents (ARLA).

A survey of residential landlord investors revealed that the average number of properties held per landlord rose from 6.3 to 7.0 in less than a year.

ARLA says this increase in 2009 ends a trend for shrinking portfolios in the buy-to-let sector, which began at the outset of 2008.

The trade body says that buy-to-let investment has increased dramatically since the early part of this decade with properties per investor increasing from four in 2004 to nearly double that amount now.

Ian Potter, operations manager at ARLA, said: “Low interest rates and proportionately higher rental yields are making the buy-to-let market attractive again to experienced investors.