British Prime Minister David Cameron today urged Libya's leaders to ensure Muammar Gaddafi's son Seif al-Islam was tried "in line with international standards" following news of his capture.
"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," 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."
Gaddafi senior, who ruled Libya with an iron first for more than four decades, was killed on October 20 when forces of Libya's new regime captured his home town of Sirte.
Cameron said the Libyan government's announcement today of Seif al-Islam's arrest in the south of the country "shows we are near the end of the final chapter of the Gaddafi regime.
"It is a great achievement for the Libyan people and must now become a victory for international justice too."
"He could have contributed to a more open and decent future for his country, but instead chose to lead a bloody and barbaric campaign against his own people.
"The fate of the Gaddafis should act as a warning to brutal dictators everywhere."
Seif al-Islam is wanted by the International Criminal Court on charges of crimes against humanity for crushing anti-regime protests.
The 39-year-old used to have strong links to Britain. He graduated from London School of Economics with a masters in philosophy, policy and social value in 2003 and took a PhD in philosophy in 2008.
But these ties became an embarrassment for the LSE once the revolt began in Libya earlier this year and the institution cut its links with Seif.
Britain was at the forefront of international efforts to support Libya's rebels against Gaddafi, and was one of the first countries alongside France and the US to launch military action under a UN mandate in March.