Fifth of Britain's second homes are in the capital

London has some of the highest concentrations of second homes in Britain.

Figures today showthere are nearly 50,000 in the capital - a fifth of the UK total.

Critics blamed multiple homeowners for pricing out first-time buyers. According to the Local Government Association, one in four properties in the City of London is a second home, the highest proportion in the country. Other hotspots include Westminster, where 10,096, or nine per cent, of properties are second homes, and Kensington and Chelsea, with 7,118 (8.3 per cent).

Tower Hamlets has 3,899 (4.2 per cent) second homes, Camden has 3,483 (3.6 per cent) and Barnet has 2,815 (2.1 per cent). The problem is made worse by the high number of properties in boroughs which have remained unoccupied for years.

In Westminster, there are 2,033 homes classified as long-term un-occupied, while in Enfield there are 1,224 second homes and 2,661 empty ones.

Croydon has 2,049 long-term unoccupied homes, Hackney has 2,639 and Harrow has 3,528.

Across England, there were 240,548 second homes in 2006, an increase of 4,217 on the previous year and more than one in 100 properties.

After the City of London, the areas with the highest proportions of second homes were the Isles of Scilly with 19 per cent, South Hams in Devon (10 per cent), north Cornwall (9.7 per cent) and north Norfolk (9.5 per cent).

LGA housing spokesman Paul Bettison said: "There needs to be a debate about how to reduce the 1.8 million people on the housing waiting lists, how we accommodate the rise in single households over the next few decades, and how we can ensure people are not priced out of their local area. In the secondhome hotspots, it can be very difficult for a young person to get on the housing ladder as demand has pushed up prices.

"People from across the public and private sectors need to sit down and work out how we can ensure everyone can have a decent home in the area where they want to live. This means we need to make best use of houses that exist.

"There are some areas with more than one in 10 properties left empty for long spells of time.

"This can lead to desolate dormitories that are bereft of spirit or life and drive house prices to unaffordable levels for local people.

"There is no one-size-fits-all solution but it is clear that councils, local people and central government will have to come up with innovative ways to prevent some areas becoming ghost towns for large chunks of the year.

"Councils want to put local people first but need the help of residents to find the solutions that would help make homes affordable without losing the economic boost that second home owners can bring."