The cost of renting a room in a shared house is soaring ahead of tenants’ budgets, it has been claimed.

Spareroom.co.uk said that the average cost of renting a room has gone up by 10% since 2009, but tenants’ budgets have not risen at all in this time because of historically low wage growth and higher costs of living.

In London, room rents have gone up 26% in the last five years, while budgets have risen only 10%.

In Scotland, where room rents have increased 24%, budgets have gone down 22%.

Spareroom puts the average monthly cost of renting in a shared house at £691 in London, £449 in the south-east, and £403 in Scotland. In all other regions of England and Wales, the costs are between £332 and £398.

The average cost of renting a room per month in the UK is currently £550 – almost a third (31%) of the average take-home pay of a full-time employee.

Matt Hutchinson, director of SpareRoom, said: “What’s clear is that affordable rents are becoming ever more scarce. Many people are still struggling with the cost of living and this isn’t being helped by the fact that wage growth is the lowest since records began.

“The problem is that we have a chronic shortage of housing in the areas where jobs are being created, so rents continue to rise as supply fails to meet demand.

“In some areas of the capital we’re seeing up to 13 people compete for every room advertised.

“The only obvious short-term solution is to encourage more home owners to let their spare bedrooms and create supply.

“To do that, the Rent A Room Scheme tax-free threshold needs to be raised to act as a proper incentive. It hasn’t been increased since 1997 and rents have risen by 103% in that time.

“Not only will this benefit renters, it could stop thousands of home owners slipping into arrears when interest rates finally rise.”

He said the tax-free threshold should be raised to £7,500 per annum from the current £4,250.