In this instance, generous family members need to consider whether their savings would be better invested elsewhere, where they could earn a higher return.

It is also worth bearing in mind that a lot of lenders place a restriction on the maximum age of a guarantor, which in many cases sits at 75 years old and can affect affordability. Parents and grandparents should be also wary of any tax pitfalls. 

This type of lending is typically more expensive than standard loans. But in some instances the security of a family guarantor is enough to reassure banks and building societies into lending first-time buyers 100pc of the property value.

‘Our first home would have been years away without it’

When Emily Stilwell and her partner were on the hunt for a mortgage with a small deposit during the height of the pandemic, they found it an impossible task.

“Any time we found something within our affordability range and which accommodated our deposit size, the lender would pull the product before we could get it,” said Ms Stilwell, a 33-year-old administration officer.

Her father suggested they take out a family mortgage, with the loan for the new property secured by the value in Ms Stilwell’s parents’ home. 

A family mortgage with the Family Building Society requires a 5pc deposit from the buyer, which can be gifted. If Ms Stilwell and her partner default on the mortgage in the first 10 years, or if the property loses value when it is sold in the same period, the bank can repossess her parents’ house to make up the shortfall.

They were able to secure a 95pc mortgage for £217,000 with the Family Building Society; without this, Ms Stilwell said it would have taken years to save up enough for a sufficient deposit. They now own a terraced house in Southampton. 

“We are a very close family and my parents trust us not to default on any payments, therefore protecting their security. For others who are this comfortable with their family, it is definitely a good option,” she added. 

Beware of the stamp duty tax trap 

Some loans, such as joint mortgages, allow parents and children to buy a property together, but also require the former to appear on the deeds of the property too. 

This can have painful tax consequences and if the guarantor already owns their own home, which is likely, they will be subject to a stamp duty surcharge of three percentage points.

One way to avoid this tax trap is to opt instead for a joint borrower, sole proprietor mortgage. This type of loan names the guarantor on the mortgage, but keeps their name off the property deed and so avoids additional capital gains tax and stamp duty liabilities. 

Mr Harris said: “Their names do go on the mortgage, however, so their income is taken into account when the lender decides how big a mortgage to give the borrower, which should mean their children can access a bigger mortgage.”

Eleanor Williams, of Moneyfacts, added: “Anyone who wishes to consider one of these specialist products would be very wise to seek independent, qualified advice – the mortgage market is a very changeable landscape at the moment.” 

Reader Service: Want to help your children get on the property ladder? Learn how equity release could help your child buy a house.

This article is kept updated with the latest advice.