DIY $O$: £75 million London mansion needs £10 million renovation

The world’s most expensive DIY job is up for sale – a £75 million property which needs a further £10million of renovation.

Number One Campden Hill is a mansion complete with staff cottage, huge garden and seven bedrooms in West Kensington, central London.

But despite its incredible price tag, the former ambassadorial residence isn’t even finished – with experts estimating the huge renovation will cost at least £10 million to complete.

Instead, estate agents Savills and Knight Frank are billing Campden Hill as a property offered with planning permission to be redeveloped into an ”extraordinary mansion unequalled in Central London”.

They claim it is a ”once in a lifetime opportunity” to purchase one of the last grand residences to be built on such a scale in the capital.

When renovated, the 60-room mansion will be spread over 30,000 square feet – making it one of the largest private homes in London.

The extensive work will take around 14 months with builders creating two subterranean levels to house a 25-metre swimming pool, squash court, cinema, gym and even a NIGHTCLUB.

There is also a three-bedroom cottage for the staff located in the 3,000 square metre garden.

Peter Mackie, managing director for Property Vision, which specialises in finding homes for the wealthy, says it is a rare opportunity but not one for an impatient buyer.

He said: ”It’s an impressive property and the quality of the garden makes it very special – it’s like a country home in the centre of London.

”But anyone buying it must have an appetite for work, there is no instant gratification with Campden Hill.

”The work, based on the planning, will probably take at least 14 months to complete and cost an eight-figure sum.”

Built in 1915, Campden Hill was the brains of Edward P. Warren, a famous architect responsible for a number of college buildings at Oxford and Cambridge University, as well as many monuments and grand residences throughout England.

It was initially owned by Colonel Grove-Hills, the President of the Royal Astronomical Society at the time.

The mansion remained almost unchanged until the early 1950s when it became home to the Uruguayan ambassador who entertained, among others, the Princess Royal at various engagements.

It continued as a diplomatic residence until January 2001 when it was sold for £17 million and has remained empty for the past ten years.

But while very little has been done to the property in the passing decade, the value has skyrocketed to £75 million – a 450 per cent increase.

It is the latest super-prime home to come onto the market in London with the demand for mega mansions forcing prices at the top-end of the property market to shoot through the roof.

And despite the colossal asking price and need for extensive work, there is expected to be no shortage of interest from Russian, Indian and Middle-Eastern billionaires looking to invest their petrodollars in a stable nation.

Mr Mackie added: ”London is a very attractive place to have a home – it’s international and people feel comfortable here.

”Believe it or not, the weather is actually a plus with Middle Eastern families preferring the weather over here in August to the heat and humidity at home.

”The leap in value reflects the scarcity of the property and its size, location and garden. When these homes are bought they rarely come back onto the market soon after.

”Historically they are retained for 20-30 years which has an effect on supply and drives the price up.”