Home truths: London's velvet underground
London's streets are falling down. At least the posh ones are. A few months ago a plush Georgian city pad at Barnes near Wimbledon, collapsed suddenly like a "tower of playing cards" (according to a witness) with one floor falling into the next and the whole lot disappearing into a vast hole in the ground. In a puff of dust, the Stg£4m six-bedroom pile was no more.
The shaky ground around Kensington and Chelsea in particular has been a concern to long-standing residents as the result of a plague of "iceberg" homes which kicked off since 2008 - spurred on by investment in London's better streets by Arab sheikhs, Russian oligarchs and celebrity millionaires from around the world. Often in recent years there have been five or six "mega basements" underway simultaneously on the same street.
Buyers who tend to live in their homes for only a few months in the year, have found the planning process to be against vast over ground extensions to these elegant Georgian and Victorian terraces, so instead they have been digging down, sometimes by as much as five floors. Typically they are doing so to create private cinemas, ballrooms, compounds for car collections, swimming pools, gyms, staff quarters and galleries for private art collections.
An extreme example is the planning permission lodged (and subsequently refused) by businessman Ed Lazarus who caused consternation when he sought approval for a 16,000 sq ft basement space (equivalent of the total floor space of 15 standard city semis). In this he planned a 25 metre swimming pool, a games room, a private cinema, a cigar room, a two storey gym complex, a yoga studio and catering kitchens.
Elsewhere a movie franchise millionaire applied for a 60 metre deep mega basement at Primrose Hill which included a banqueting hall, a swimming pool and staff quarters.
In 2001 the borough of Kensington and Chelsea received 46 applications for basement excavations and works but this has since peaked at 450 three years ago. Most take a year or more to complete with constant noise disruption, dust and serious structural and safety risks to neighbours.
It has meant the "old money" celeb neighbours are up in arms - Joan Collins said it was shocking that "people are digging down to put in swimming pools and bowling alleys when they only live here for two or three months of the year". Queen guitarist Brian May set up a Twitter hashtag called #BasementBulding-Bastards and has described his neighbours as "selfish and brutish" and the piling machine as an instrument of torture.
And they do have real concerns because the homes of residents next door to or near mega basement excavations have regularly suffered from knock on subsidence or cracking. One resident who was staying next door to a house being excavated had to call for help after he found he couldn't get out - all the windows and doors in had jammed shut due to a sudden subsidence.
At one point a hole opened up in a street in Belgravia big enough to swallow a skip. There are long running court cases where neighbours are seeking damages for cracking and structural damage.
The "new money" diggers are also incentivised financially to incense their neighbours - one London estate agent has estimated that every additional square foot of basement space costs Stg£500 but adds Stg£1,000 to Stg£5,000 to the property's overall value.
Finally, miffed residents' groups of the "old money" mega rich gathered together to fight the oligarchs and sheikhs in London and persuaded the Chelsea and Kensington Council to legislate to end mega basements and iceberg homes.
The new rules introduced last year restrict underground development to a single storey, by how far it can run under a garden and in the case of listed buildings, have curtailed them altogether. It is expected that other councils there will follow.
Because it can take years to complete a mega basement, the last few are currently being excavated but eventually the drumming of the pile drivers and the unexpected sink holes will cease.
Thankfully in Ireland, it is still not economical, even in expensive city locations, to dig down deep as it is in London where these homes can fetch the equivalent of €20m.
But there is still some kick left in those who want to dig under London. Zipporah Lisle-Mainwaring (71) took a high court case to quash the new planning policy after it was used to block her plans for a two-storey basement. It faltered in July last year when the court ruled that the council's legislation was fair.
And in answer to her neighbours, who objected every step of the way to her plans to dig down, Lisle-Mainwaring opted to paint the entire three storey double frontage of her period Kensington home in loud red and white candy stripes. So there.