How to spend £30m on DIY

The woman in charge of renovating the most expensive house on north London's billionaire's row, has been explaining why after spending a record £50m on the property, it requires a further £30m to make it just so. "There have been a lot of technological improvements since this house was built," said Yassmin Peramaa. "Mother-of-pearl tiles, for instance, didn't exist then."

Yassmin has been put in charge of works at the Toprak Mansion - known locally as Top Whack, and now renamed Royal Mansion - by her mother-in-law, one of the most unlikely billionairesses to come to London for a long time.

Hourieh Peramaa is 75. When she fled her native Kazakhstan at 17 she ended up in an Iranian refugee camp with nothing to her name. There she met her future husband Horelma, a medical student from a wealthly Kazak family. She helped him amass a property portfolio in Iran and across Europe, now worth more than £1bn.

Yassmin has a team of builders ready to rip almost everything out of the house. Her £30m budget will be spent on such modern necessities as a 30-seat cinema, a 24-carat gold-plated whirlpool bath, the installation of a small river through the gardens, and a helicopter landing pad which will sink into the ground, while a roof slides across to hide it. "My mother-in-law has high standards," says Yassmin.

The agent who sold the house, Trevor Abrahamson of Glentree International, says a lot of people looking for properties of this kind in London "come from troubled areas of the world and are buying a bolt-hole against anything going wrong at home. It is also a statement of their wealth."