A banker won a marathon court battle against a "purchaser from hell" who ripped out parts of his £800,000 house and built an unauthorised extension.

Jess Shakespeare, 43, and Emma Purdie, 49, a web developer, inherited their late mother's house in Chorleywood Road in 2011 and agreed to sell it to builder David Lewis in 2013.

Although the sale had not been completed, the siblings allowed Mr Lewis early access to do work in the garden.

But London's High Court heard Mr Lewis, 55, went on to remove the kitchen, demolish a fireplace, build an extension and fell protected trees.

When he ignored a stop notice from the local planning authority, it issued proceedings.

Even though the siblings' had not consented to the work, they were named as defendants alongside Mr Lewis and ended up paying legal costs.

The sale fell through and after a two and a half year legal battle, Judge Andrew Keyser ruled the builder cannot have his £73,000 deposit back.

Mr Lewis, of Chalfont St Giles, also faces legal bills of £47,000.

The judge said he had 'significantly exceeded' the permission he was given.

Mr Lewis insisted that the work he did on the property improved it and made it more valuable.

But the siblings' barrister, Tom Weekes, said: "They regret agreeing to sell the property to Mr Lewis. He has been a purchaser from hell."

Mr Lewis's barrister, Timothy Sisley, said the builder claimed Mrs Purdie's husband had "broadly approved" the works.

Although he initially tried to force the siblings to go through with the sale, by the time the case reached court Mr Lewis was claiming there had never been a valid contract.

But the judge ruled Mr Shakespeare and Mrs Purdie had validly cancelled the deal and Mr Lewis had forfeited his deposit.