A large proportion of first-time buyers in Britain are leaving themselves overstretched and underprotected when it comes to paying their mortgages.

A new study by Post Office Financial Services found that 48 per cent of UK first-time buyers would only be able to meet mortgage repayments for six months if they lost their job tomorrow.

The report notes that the average house deposit has soared to £11,710,2 and household costs, such as utility bills have soared in recent years, leaving many first-time buyers overstretched financially.

Almost half of the first time buyers quizzed (45 per cent) admitted that they had not taken out any kind of protection against loss of income as a result of accident, sickness or unemployment.

Reasons for failing to take out payment protection insurance include believing it is too expensive and not needing it. A fifth of first-time buyers (21 per cent) polled said that they would rely on friends and family to meet repayments in the event of loss of income, while one in 20 think they would have to sell their home.

"First-time buyers tend to overstretch themselves, but need to consider what they would do if they lost their income," Post Office head of marketing, Claire Oldstein, said. "It's unlikely they will have a big enough rainy day fund to rely on - especially after pulling together a deposit."

Payment protection insurance can cover outgoings, such as mortgage and loan repayments for up to 12 months if someone is unable to work as a result of accident, sickness or unemployment.

The number of people defaulting on mortgage and loans in Britain has risen in recent year after the level of debt in Britain soared to more than £1 trillion and a decision by the Bank of England's monetary policy committee to raise the base rate of interest to 4.75 per cent will affect borrowers.