So apparently punishing terrorists (assuming we had the right people in the first place) isn't quite as important as U.S. and British officials make it seem. It's all about the oil, baby!

The British government decided it was “in the overwhelming interests of the United Kingdom” to make Abdelbaset Ali Mohmed al-Megrahi, the Lockerbie bomber, eligible for return to Libya, leaked ministerial letters reveal.

Gordon Brown’s government made the decision after discussions between Libya and BP over a multi-million-pound oil exploration deal had hit difficulties. These were resolved soon afterwards.

The letters were sent two years ago by Jack Straw, the justice secretary, to Kenny MacAskill, his counterpart in Scotland, who has been widely criticised for taking the formal decision to permit Megrahi’s release.

The correspondence makes it plain that the key decision to include Megrahi in a deal with Libya to allow prisoners to return home was, in fact, taken in London for British national interests.

Edward Davey, the Liberal Democrat foreign affairs spokesman, said: “This is the strongest evidence yet that the British government has been involved for a long time in talks over al-Megrahi in which commercial considerations have been central to their thinking.”

Two letters dated five months apart show that Straw initially intended to exclude Megrahi from a prisoner transfer agreement with Colonel Muammar Gadaffi, under which British and Libyan prisoners could serve out their sentences in their home country.

Downing Street had also said Megrahi would not be included under the agreement.

Straw then switched his position as Libya used its deal with BP as a bargaining chip to insist the Lockerbie bomber was included.

The exploration deal for oil and gas, potentially worth up to £15 billion, was announced in May 2007. Six months later the agreement was still waiting to be ratified.