It seems that not a week goes by without one multi-millionaire or another leaving their (very expensive) mark on the inflated London property scene.
This week it's the turn of Russian-born tycoon, Leonid Blavatnik whose grade II-listed Victorian extravaganza could now be worth a phenomenal £200million, according to estate agents in the know.
Mr Blavatnik - who comes in at a very respectable second on Britain's rich list - is just months away from completing a two-year renovation project on his west London property, sending ripples of excitement through the property sector.
Will he sell? Will he keep the property on Kensington Palace Gardens as his London des res? The capital's high-end property brokers are on tenterhooks...
Self-made millionaire, Blavatnik - owner of the Warner Music Group, paid £41million for 15 and 15b on the exclusive street in 2004 after a rumoured bidding war with rival Roman Abramovih and Lakshmi Mittal.
Once his extensive modernisation is complete, the 13-bedroom, nine-bathroom property will feature an impressive 25-metre swimming pool with indoor and outdoor sections, a gym, cinema and spacious wine cellar as well as a multi-story underground car park complete with a lift so guests can avoid troublesome traffic wardens.
And for the security conscious the property is protected by armoured glass and will also house a two-bedroom security post once complete.
Giles Hannah of Mayfair-based agents VanHan told the Evening Standard: 'It is one of the best [properties] on the street, wiht a particularly large garden and fantastic views overlooking the lawns of Kensington Palace.
'He's doing it to a phenomenal stardard. It has vast ceiling heights...'
One thing's for sure, he probably doesn't need the money. According the Sunday Times Rich List, Mr Blavatnik's wealth is estimated at around £11billion.
If he does sell, 15 Kensington Palace Gardens will still be some £50million shy of the asking price for a property on Carlton House Terrace. If it sells for £250million, the terrace property overlooking St James' Park will smash the record for the UK's most expensive home.
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