Buy-to-let mortgages accounted for a record 12 per cent of new loans in the first half of this year, new figures showed yesterday.

A report from the Council of Mortgage Lenders found that buy-to-let loans now represent 10 per cent of all mortgage balances, up from 3 per cent five years ago.

That increase comes despite a series of interest rate rises.

Homeowners and investors have endured five quarter-point rises in interest rates since last August, taking the Bank of England’s base rate to 5.75 per cent, but most economists expect that to rise to 6 per cent this year.

However, only 0.63 per cent of buy-to-let loans were three months or more in arrears in the first half, compared with 1.06 per cent of all loans in arrears, CML figures revealed.

The figures came as it emerged that first-time buyers are spending a record multiple of their salaries to put a foot on the bottom rung of the housing ladder.

First-time buyers borrowed a record multiple of 3.37 times earnings in June, up from 3.22 times the year before.

Fionnuala Earley, the chief economist at Nationwide, the country’s largest building society, said: “It may be too early to say whether we are creating a two-tier society of homeowners and renters but it is clearly becoming difficult for those on lower incomes or those without access to deposits – from their parents’ housing wealth or their own savings – to get on the ladder.”

The figures from the CML also reveal that loans to first-time buyers in June, usually one of the busiest times for the housing market, declined to 35,600 compared with 39,800 first-time buyer loans taken out a year ago.

Yolande Barnes, the head of residential research at Savills, the property agents, said: “The loan-to-income multiple is a big rise and worrying in the light of rising interest rate rises. The chance to get on the housing ladder is limited to a few. Lower income purchasers are being cut out of the market. You can multiply up [your borrowing] more as you go up the income scale.”

The plight of lower income earners in London will worsen where house prices continue to rise. Most first-time buyers are also being hit by higher stamp duty because the average price of starter homes in the capital exceeds the £250,000 threshold at which the tax triples to 3 per cent. .

Simon Rubinsohn, the chief economist at the Royal Institution of Chartered Surveyors, said: “The additional layer of demand from buy-to-let investors has had some affect on the first-time buyer market but some people are making lifestyle choices with a thriving rental sector giving more flexibility on where to live.”

Nigel Terrington, the chief executive of Paragon, the country’s largest specialist buy-to-let lender, said: “There is a shortage of housing in the UK and recent waves of immigration compound that problem. If you want the Government to do something other than relying on interest rates to control house price inflation, they simply have to build more homes.”