Second-home owners and buy-to-let investors are set to reap vast tax savings on profits from their properties when new capital gains rules come into place next April.

The Chancellor on Tuesday unveiled plans to to introduce a flat Capital Gains Tax rate of 18 per cent and abolish taper relief as part of wider plans to raise £900 million over three years by taking a cut from private-equity profits.

But the moves will benefit wealthier property investors, or those who have held on to a former home, as crippling capital gains tax bills will be slashed.

Higher-rate taxpayers who sell a second property pay between 24 per cent and 40 per cent in tax on any gains they make over £9,200. But from next April, they will pay just 18 per cent tax.

One in ten people in the UK own a second property, whether as a holiday home or a buy-to-let investment, according to a recent survey from Nationwide Building Society.

Property experts believe the new cheaper “escape route” for owners could cause short-term turbulence as higher-rate taxpayers delay selling property until the new tax regime comes into force, but will ultimately breathe life into the market next year.

Lucien Cook, director of research at Savills, the estate agent, said: “The removal of the tax advantage achieved from long-term ownership could mean that there will be more trading of property and more liquidity." But homeowners worried that house prices will fall as a result of increased supply should not worry. "I don’t think the tax tail will wag the dog of house prices," he said.

This is welcome news for homeowners as the market weakened in recent months amid higher borrowing costs and slowing prices. Areas which attract second home owners and buy to let investors such as coastal resorts and University towns will benefit the most from increased activity next year.

Liam Bailey, head of research at Knight Frank, said the changes would help to support the investment property market in the UK and abroad. He said: “This is a big change and could have the effect of raising investment volumes — and hence underpin prices — in investment and second home locations.”

There had been fears that investors, who have become used to high capital gains, would begin to sell up amid forecasts for stagnant prices through next year. But a recent sharp rise in rents across the country ha s encouraged many landlords to hang on to their properties. This week the Council of Mortgage Lenders revealed that buy-to-let lending, up 37 per cent in a year, was helping to prop up the flagging homes market.Higher-rate taxpayers who sell a rental property or second home currently pay an effective rate of between 24 per cent and 40 per cent capital gains tax on any gains of more than £9,200 they make. Taper relief means that the longer they have held the asset, the less tax they pay.

But from April, higher rate taxpayers will have to fork out only 18 per cent in capital gains tax, regardless of how long they have held the asset. A landlord who wants to sell a £330,000 property he bought two years ago for £250,000 will save more than £15,000 in tax by selling after April 6. If he sells before the new regime comes into force, he will have to pay £28,320 in CGT; after April 6, his liability will be just £12,744.

A couple who bought a holiday home in 1993 for £302,000 who sell it for £685,000 will save nearly £8,000 in CGT if they complete the sale after next April.

Carolyn Steppler, private client tax director at KPMG in the UK, said that for most investors and second home owners “the capital gains tax they will pay on taxable profits arising from the sale of a second property is cut by over half.”

But lower-earners will lose out under the new deal. As CGT is charged at the same rate as income tax, which will be levied at 20 per cent from next April, basic rate taxpayers who have held an asset for four or more years pay an effective rate lower than the new 18 per cent rate once taper relief kicks in, falling to 12 per cent after ten years.

Matt Coward, of Blick Rothenberg, the accountant, said: “One of the consequences of the new rules is that basic rate taxpayers who have held investments for a long period of time will suffer a significant increase in their tax liabilities, from 12 per cent to 18 per cent on their gain. "

For example, a couple who pay basic rate tax who moved from two homes into one ten years ago when they got married, will have to pay more in CGT if they decide to sell the second house. If the house was bought for £109,000 and sold for £250,000, the CGT payable before April 6 is £3,368 less than if the property is sold after April next year.

Sanjay Arora, a buy-to-let investor with a portfolio of 38 properties, said: “There are lots of ordinary Joe Bloggs buy-to-let investors who have just started out. They are investing for their future or for their children and do not have a large portfolio, and they are lower-rate taxpayers.”

Good prospects for letting a property or the potential for house prices increases were cited as the most important factors in deciding where to buy a property by almost half of those surveyed by the lender.