On another occasion, an investigator went to Southampton and noticed an unusual level of media activity. It turned out that the property under investigation backed on to a house in which there had been a murder. This proved too much for the buyer. “I recall standing outside one flat on a Friday night when a couple started rowing on the balcony,” says Parsons.

“She was screaming at the top of her voice and he ran downstairs. He got in his car and screamed off, hitting two other cars in the process. After talking to the neighbours, I discovered the pair did that sort of thing every weekend.”

The so-called Neighbours service forms about 5% of Parsons’s work, with clients including children who are moving elderly parents and want to make sure they will be safe, companies relocating staff, and foreign buyers, such as the woman from Boston, Massachusetts, who pulled out of her sale after discovering that Brixton, in south London, was not quite the glamorous location that she had been imagining.

Of course, you need not employ a detective agency — you can do your own house detecting. Here are Parsons’s tips: look around the house. See what’s left, what’s right, what’s opposite. Go to the pub. If it’s a friendly, local pub you are probably moving into a friendly neighbourhood.

See what local people say. Ask questions at the newsagent, at the post office. The postman, the milkman and the people at the corner shop are all good sources of information.

Local authorities will also provide information about noisy or nuisance neighbours as part of the usual local search. “If a complaint has been made against a neighbour, it will show up in the search,” said a spokesman for Westminster city council.

The house detective service started by accident. “It had never occurred to us, to be honest,” says Parsons. “But a corporate client had a nightmare neighbour, decided to move, and wanted to make sure he didn’t make the same mistake again.”

This is how he sums up the service: “We paint a picture of what life will be like when the estate agents have gone away.”

Perhaps it is because of comments such as this that estate agents are not all that keen on this service. Hugh Dunsmore-Hardy, chief executive of the National Association of Estate Agents, has described such investigations as “not a particularly good investment”. He added: “If you are unfamiliar with an area, walking round and chatting to locals will usually throw up any problems.”

Sometimes, of course, you don’t have to tour the neighbourhood. The neighbourhood will come to you. “A colleague has just moved into a block of flats,” says Parsons. “She is 25 and had just got settled when an elderly neighbour came down. ‘I hope you’re not going to make any noise,’ the neighbour said. My colleague hadn’t made any noise at all. The neighbour just assumed that, as she was young, she would.”

Perhaps there’s a gap in the market there. If a detective can check out the neighbours, why not the buyers too?

Answers Investigation, 01483 423 900, www.answers.uk.com

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