albrini
© AFP/Getty ImagesAlbrini was filmed on CCTV travelling to Paris two days before the massacre, which killed 130 people, in November
'The man in the hat' linked to terrorist attacks in Paris and Brussels has become the first ISIS Supergrass for British police.

Mohamed Abrini, 31, is facing terrorism charges after he was spotted at Brussels Airport with two of the suicide bombers in March. He was dubbed 'the man in the hat' as he was wearing a white jacket and a dark-coloured hat, while he pushed a trolley through the terminal. He was also filmed on CCTV travelling to Paris two days before the massacre, which killed 130 people, in November.

Abrini, from Belgium, has been helping British officers with intelligence on potential terrorist attacks and jihadists in the UK, according to the Sunday Times. A Supergrass is a police informer who implicates a large number of people, in return for immunity from prosecution, a more lenient sentence or new identity.

Belgian authorities have reportedly been asking questions to Abrini on behalf of British police.

On Thursday, a Belgian appeals court upheld a judge's ruling that Abrini can be extradited to France to face justice there. Belgian prosecutors have said they don't expect the suspect to be handed over to French authorities anytime soon.

He is also being investigated for his links to the suicide bombers who struck the Brussels Airport and subway on March 22, killing 32 people.

'No additional information will be given regarding further proceedings,' the Belgian Federal Prosecutor's Office.

It was announcing the Brussels Court of Appeal's rejection of Abrini's challenge to a June 9 lower court decision that an arrest warrant issued for him by France is enforceable.

In separate proceedings, a Brussels judge ordered to extend the custody that Abrini, his 20-year-old brother Ibrahim Abrini and four other people detained in Belgium in connection with the attacks that killed 130 victims in Paris on November 13, 2015, be kept in custody for another month.

Responsibility for the Paris carnage and Brussels bombings was claimed by the Islamic State extremist group.