Buy-to-let investors are emerging as one of the surprise beneficiaries of the famine in mortgage lending, according to new research.

The share of residential housing stock owned by private landlords has jumped more than 40pc since the financial crisis, and now makes up almost a fifth of the total, according to estate agent Savills.

The tighter lending standards introduced by Britain's banks since the crisis have created opportunities for some investors, as the pool of potential homebuyers shrinks.

And, according to Savills, rather than the house price appreciation that lured investors during the boom, it is the prospect of rising rental income that is proving attractive.

The volume of mortgages handed to private landlords jumped 16pc to £3.8bn in the third quarter of last year, according to the Council of Mortgage Lenders.

Despite the sharp drop in house prices since the recession, and the expectation of a further decline this year, first-time buyers are struggling to secure a foothold on the property ladder.

Evidence of a resurgence in buy-to-let investors is likely to increase political pressure on the Government to take measures to help first-time buyers.

The booming rental market is being echoed in America, where the collapse of the economy's house price bubble is forcing more people to rent.

Home ownership levels dropped to 66.9pc last year from 70pc in 2005.