A multi-millionaire hedge fund tycoon has been told to pay more than £800,000 by Kensington council in order to add a two-storey basement to his mansion in a property trend of "iceberg homes".
Reade Griffith, the 48-year old founder of Polygon Investment Partners, and his wife Elizabeth, 42, plan to build the vast extension under two adjoining Kensington townhouses at an estimated cost of £4 million.
The basement excavation, measuring around 900 square metres (9,000 square ft), would house a spa, swimming pool and "treatment area". The size of the basement is the equivalent to eight-average sized new-build family homes would add £10 million to the property's value.
Property experts have expressed shock at the size of the development and warned that more lavish planning applications could come before October, when Kensington and Chelsea's planning regulations are set to restrict the size of potential excavations.
The project was applied for in Mrs Griffith's name, who owns one of the properties, while her husband owns the neighbouring house through a company.
However, the extension's scale means Kensington and Chelsea Council have required a one-off £825,000 fee in order for it to grant planning permission, which would go towards affordable housing elsewhere in the borough.
Such payments, under "Section 106 agreements", normally apply to large-scale commercial developments, instead of single private planning applications.
Stuart Robinson, head of planning at the global property agents CBRE, told the Financial Times that the size of the project was "off the scale".
"My goodness, I’ve never heard of anything like that. This is completely off the scale. You don’t normally get these agreements with residential applications," he said.
Richard Barber, partner at W.A. Ellis, told the Huffington Post UK: "I'm shocked at the size of the extension and the size of the fee they're suggesting. 9,000 square feet is enormous. It's well out of the range of normal extensions."
"They're obviously trying to get this in before the big change in october. Kensington and Chelsea are reducing the amount of area that you can create under a garden in floorspace from 80% to 50% of its size. "
"We'll likely be seeing a rush of others doing this before the deadline. I imagine the council will have many more planning applications."
Edo Mapelli Mozzi, of high-end property developers Banda Property, told the Huffington Post UK that the £825,000 fee could be an attempt to put the Griffiths off their project.
"The project is absolutely ginormous. But the fee would be a headline figure to start off with, then it comes down to a question of viability."
"It could be a kind of way to delay it to the point where they have to redraw it and resubit it and they realise they are not going to get it."
Jo Eccles, MD of Sourcing Property, said the council's move was a "political ploy" against people who wanted to "add value to their property".
Basement excavation planning requests for have soared in Kensington and Chelsea in the last decade, increasing from 13 in 2001 to 307 in 2012.