THE amount of value an extension will add to your home varies greatly across the UK, figures reveal.

Experts at the Office for National Statistics have listed the average price of properties “per square metre.”

The figures, covering England and Wales from 2004 to 2016, can be used to predict how much a home would be worth following an extension.

Of the 20 most expensive UK areas, 19 are in London. 

Kensington and Chelsea is the most expensive borough, where houses and flats are worth about £19,439 per square metre.

Even properties in the capital’s least valuable area, Barking and Dagenham, are worth £3,994 per square metre. This is more than twice the value of properties in Manchester and Birmingham and £1,833 more valuable than those in Cardiff. 

The cheapest properties can be found in Blaenau Gwent, Wales, at £777 per square metre.

Wales overall had the second lowest value of the regions covered, with just £1,408 per square metre, compared to £1,271 in the North East and £1,543 in the North West.

The average price per square metre rose by 28 percent in Wales over the past 12 years and 44 per cent in England. This is great news for those who already own their own home.

In a separate report by Plentific, Barking and Dagenham was found to be the UK’s biggest property-renovation hotspot, with an increase of 114 per cent in the number of renovation applications in the last two years.