Nairobi — A year after the Lockerbie bomber was released from a Scottish prison, Britain warned Libya not to celebrate the anniversary today, saying to do so would be "tasteless, offensive and deeply insensitive".

Abdelbaset Ali Mohmet al-Megrahi was thought to have only three months to live because of terminal prostate cancer when he was freed on compassionate grounds and returned to his homeland Libya to a hero's welcome.

But he has defied his prognosis, to the dismay of the mainly American relatives of the 270 people who died when Pan Am Flight 103 blew up over the Scottish town of Lockerbie, four days before Christmas in 1988.

Scotland's First Minister Alex Salmond again defended his government's decision to free Megrahi in a round of interviews today, telling the BBC it acted "in good faith on the information that was available at the time".

"No-one could have absolute certainty (about how long Megrahi would live)," Salmond said. "That was a reasonable expectation of his life expectancy."

Earlier, the Foreign Office issued a strongly-worded statement urging Libya not to hold celebrations honouring the only man "convicted for the worst act of terrorism in British history".

"Particularly on this anniversary, we understand the continuing anguish that Megrahi's release has caused his victims, both in the UK and the US," a spokeswoman said.

"Any celebration of Megrahi's release will be tasteless, offensive and deeply insensitive to the victims' families."She added: "We have made our concerns clear to the Libyan government."

Britain's ambassador to Tripoli, Richard Northern, has told senior Libyan government officials that any public events honouring Megrahi could damage warming ties between the two countries, the Guardian newspaper reported.

Salmond added it would be "totally inappropriate" for Libya to celebrate the anniversary.

Questions remain about the precise circumstances of the release, though, with US senators demanding more information on the case.

The US Senate's Foreign Relations Committee is to hold a hearing on Megrahi in the coming weeks.

This will examine whether oil giant BP -- already facing intense pressure in the United States over the Gulf of Mexico oil spill -- played a part in securing Megrahi's release in a bid to safeguard a $900 million exploration deal with Libya.

BP denies this and the Scottish government has refused to send ministers to Washington to appear before the hearing, saying there are no more documents it can release on the affair.

Most of those on board the passenger jet were from the United States, where many relatives strongly opposed 58-year-old Megrahi's release after serving eight years of a minimum 20-year term.

"He's lives his life now as a free man surrounded by his family and certainly not a privilege that my husband had," Mary Kay Stratis, whose husband Elia was killed in the bombing, told the BBC. "We need some answers". (AFP)