Prime Minister David Cameron said on Saturday it was important that Muammar Gaddafi's son Saif al-Islam, captured by fighters in Libya, should receive a trial in accordance with international standards.
It is a great achievement for the Libyan people and must now become a victory for international justice too, Cameron said in a statement.
Britain will offer every assistance to the Libyan Government and the International Criminal Court to bring him to face full accountability and justice for what he has done.
The Libyan Government has told us again today that he will receive a trial in line with international standards, and it is important that this happens.
(Reporting by Michael Holden)