Britain's former defence minister Liam Fox admitted on Wednesday he should have been more willing to listen to concerns raised about his links with a close friend which cost him his job.

But Fox said he had been victim of "vindictiveness, even hatred" from the media.

He apologised for letting his colleagues down and breaching the code governing the conduct of ministers, but told lawmakers the "media frenzy" around his links with his friend Adam Werritty "should worry all of us".

Fox, who resigned on Friday after a week of intense pressure over claims that 34-year-old Werritty posed as his official advisor on trips abroad, faces a probe from a parliamentary standards watchdog, it was confirmed on Wednesday.

In his statement to the House of Commons, Fox said: "I am very sorry for letting colleagues down.

"I accept that it is not only the substance but perception that matters, and that is why I chose to resign."

However, in an indication he will seek to protect Werritty, who acted as his best man at his wedding, Fox said "you do not turn your back on your friends or family in times of trouble".

He added: "It is, however, unacceptable that family and friends who have nothing to do with the central issues should be hounded and intimidated by elements of the media, including in this case elderly relatives and children."

An official report into Fox's actions has found that he caused a security risk by leaking details of future foreign trips to Werritty.

Despite having no government role, Werritty accompanied the minister on a series of overseas visits, with his travel funded by backers linked to Israel and Sri Lanka.

Another government minister from Prime Minister David Cameron's Conservative Party, Greg Barker, who holds the climate change portfolio, was accused Wednesday of similar charges of blurring the role of a close advisor.

The Guardian said Dutch-born consultant Miriam Maes -- who also works for a company whose clients include airports operator BAA and Morgan Stanley -- was given a job in his department and handed out business cards bearing its name.

The Department for Energy and Climate Change denied she was a formal government adviser to Barker, saying her role was to advise his department, not the minister personally.