Extra-long term mortgages on family homes which could be passed on from parents to their children are being considered within Government as part of plans to ease the housing crisis.

The idea could see people able to buy a home with little or no expectation of completing mortgage repayments during their lifetime, instead the property and outstanding debt would be passed on to their children.

Mortgages lasting 100 years have been issued in Japan but experts were sceptical about the impact the proposal would have in the UK.

The idea has been floated within government as it could allow people to buy a bigger home than they otherwise might be able to afford.

The Government is already trying to increase home ownership with a package of measures including extending the right-to-buy to housing association tenants and trying to increase access to 95% mortgages for buyers struggling to save for a larger deposit because of high rent levels.

Asked if he was considering cross-generation mortgages that could be passed between parents and children, Boris Johnson told reporters: “Yes, certainly.”

Setting out his plans to get more people on the property ladder, the Prime Minister said: “I do think there’s a lot more scope to help people with 95% mortgages, there are quite a few products available now, which we’ve tried to encourage.

“But also, we want to find all sorts of creative ways to help people into ownership.

“Last year, actually, we had 400,000 first-time buyers, that’s a great number, we’re starting to turn the tide, but it is crucial for this Government and for our overall economic story if those numbers continue to be strong.

“We need young people to have the confidence, to have the deposits, the mortgage packages to be able to get into ownership.”

The most popular mortgage length among first-time buyers is around 30 to 35 years but a multi-generational approach could extend that by decades.

However, commentators warned it would not address problems of housing supply and could further drive up property prices.

Scott Taylor-Barr, financial adviser at Carl Summers Financial Services, said: “I feel that Boris is coming at this from the wrong direction.

“It is not the mortgage market that is preventing people from becoming homeowners; it is the cost of property in relation to people’s earnings.

“The issue isn’t to find ways to help people take on more debt, we need to find ways to build more houses, in the areas people want and need to live.”

Rob Gill, managing director at Altura Mortgage Finance, said: “We are turning Japanese. A decade of ultra-low interest rates, followed by inter-generational mortgages which have been a feature of the Japanese mortgage market since the mid-90s.

“Low interest rates boost property prices, long mortgage terms then keep them going as the only way first-time buyers can get on the ladder.

“It seems governments the world over will do anything to avoid the alternative of property prices actually falling.”