Cherie 'cuffs' a cheeky boy

Police investigate claim that Prime Minister's wife aimed light-hearted slap

Police have investigated the behaviour of Prime Minister's wife Cherie Blair after claims she aimed a slap at a teenage fencing champion for being cheeky. Seventeen-year-old Miles Gandolfi had made a "bunny ears" sign behind her head.

The incident happened at the UK School Games in Glasgow last week, where Mrs Blair was photographed waving a sword. The involvement of detectives did only come to light yesterday.

Mr Gandolfi, from Orpington, Kent, was captaining an under-17 épée team. While being photographed with the guest of honour he is reported to have put his arm around her before making the bunny ears sign. Mrs Blair spotted it and apparently slapped him on the back saying "cheeky boy". She quipped: "It's lucky I have a sense of humour."

Mr Gandolfi and his family are said to have been embarrassed at the incident, which was seen as light-hearted, as well as the later police involvement. His mother, Catherine, said the teenage sportsman had been "larking about" and later apologised to Mrs Blair. "It wasn't an assault or anything like that. It was just a bit of fun on his part. She's had teenage boys so she knows what they're like," Mrs Gandolfi says in today's The Mail on Sunday. "Miles made a statement to the police in Glasgow. I have absolutely no idea why it all blew up. It just seems totally bizarre. We couldn't believe it when the police got involved."

The playful slap was reported to the police by a witness and plain clothes detectives went to the school games in Glasgow the next day to interview the boy. At least six detectives from Strathclyde's serious crime squad arrived at the sporting event. Mr Gandolfi was interviewed by child welfare officers and two detectives.

Downing Street said last night: "The Strathclyde police undertook an investigation, including taking statements from a number of people ... These included the 17-year old boy involved and Mrs Blair's protection officer, who was with her at all times, who said that nothing had occurred between Mrs Blair and the youngster. We understand no further action is planned."

This is not the first time Ms Blair, a part time judge, has had a brush with the law. In 2000 she was fined £10 for travelling on a train without a ticket. Seen by some as accident prone, she caused embarrassment to the Government over her friendship with Carole Caplin, the lifestyle adviser who was once photographed applying her makeup. It later emerged that Mrs Blair had involved Ms Caplin's boyfriend, a former conman, in purchasing property in Bristol for her eldest son Euan while he was at university.

There has also been controversy over the size of fees she has charged for lectures abroad and a shopping trip in Australia in which she was forced to pay for a pile of clothes she had been given as a freebie. However, the latest incident appears to be over. Last night Strathclyde police said: "Inquiries into the matter are now complete."