By Hugh Dunnett, Crime Correspondent

A dodgy builder persuaded a vulnerable old lady that her whole roof needs replacing as a matter of urgency.

The trickster knocked on the door of the large, detached residence in central London and persuaded the elderly resident that repairs were essential.

But after marching the grey-haired great granny to a cashpoint to withdraw £200,000 as an upfront payment for the work, a group of nearby sleuths cottoned on to his devious plan and put a stop to it.

Local police spokesperson Constable Lorraine Fisher, 34, said: “What sort of a person tries to trick an old lady like this?

“One of the tiles on her roof was slightly loose but he persuaded her the whole lot needed replacing. He then quoted her £200,000 which he wanted as an upfront payment. In cash.

“The poor resident was completely taken in as he seemed like a genuine sort, and she didn’t want her roof to leak.”

Constable Fisher said the builder, described as dishevelled and slightly deranged, was only stopped when 11 members of a local law society spotted what he was up to.

One of the group, a rather dour lady with a large pet spider on her jumper, gave him a right rollicking and told him he was being unlawful. She said he had told untruths to the elderly lady and should get back to his proper job immediately.

The victim had her money returned and is said to be none the worse for her ordeal.

A family friend said: “She said if he comes around here again, it’s orf with his head.”

Image: Boris part from Andrew Parsons/ i-images under CC 2.0