Mystery of night police were called to Liam Fox's flat

It was a deeply disturbing experience for Liam Fox, finding that his home had been burgled while he slept. The potential for violence was illustrated by knives taken from kitchen drawers and lined up ready for use by the intruders if they had been challenged.

At the time, April last year, Conservative Central Office stated that Mr Fox, then the shadow Defence Secretary, had been alone at his £500,000 London apartment as his wife, Jesme Baird, had been stranded in Hong Kong by the Icelandic ash cloud.

So concerned was Mr Fox that he telephoned Boris Johnson to ask why the police were not doing more to prevent break-ins. The Mayor was busy, so he spoke to his deputy, Kit Malthouse. Staff at the Mayor's office were mystified that the Tory defence spokesman would be so keen to let it be known that he had been burgled.

The police were puzzled that there was no sign of forced entry; Mr Fox explained he had left a window open because it was so warm. A Skoda car, a mobile telephone and a laptop were stolen – along with, it was claimed, briefing papers for the second televised debates between the three party leaders in the election campaign.

Following an investigation, three youths, two aged 14, one 17, and two men aged 19 and 22 were arrested. Only the 17-year-old was convicted. He was given a year's rehabilitation order.

The burglary played a key part in the decision to relocate Mr Fox, now Defence Secretary, to a flat at Admiralty House in Whitehall, at a cost to taxpayers of £95,000 a year. He is the only minister to have been given such accommodation. He was also allocated a £150,000 bullet-proof, chauffeur-driven BMW 7 Series limousine.

It now transpires that Mr Fox was not alone on the night of the burglary after all. He had been out drinking with a friend, described as a "younger man", whom he allowed to stay overnight.

Mr Fox said in a statement: "As I told police at the time, a friend was staying in the guest room. My wife was stranded in Hong Kong due to the ash cloud. For the sake of clarity it wasn't Adam Werritty. I was a victim of a violent crime and I'm appalled at being portrayed as having something to hide. We're trying to establish why the media were given the impression I was alone." The Defence Secretary refused to identify his guest for the night.

Security sources disclosed it was not just the danger of break-ins to Mr Fox's home that concerned them. The Defence Secretary had been paying regular visits to pubs and clubs near his London Bridge flat. Some, it was felt, were potentially risky because of the types of customer they attracted.