Under the plans, borrowers could borrow larger sums, then pass the loans down to their children, along with the property, when the original owner retires.

Speaking to reporters during his trip to the Nato summit in Madrid this week, Boris Johnson confirmed the 50-year mortgage idea was being considered, saying the government “wants to find all sorts of creative ways to help people into ownership”.

The Prime Minister added: “Last year 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. If you’re good enough to pay a lot in rent, we should find ways to help you to convert that into a mortgage.”

When asked if he was considering ultra-long mortgages, he replied: “Yes, certainly.”

Other plans being considered by Downing Street include attempting to free up government-owned land for rapid homebuilding, and exploring whether institutions such as schools can build homes for key workers who cannot afford to live in local areas, The Telegraph reports.