Assad Uzzaman, 25, was one of five men from Portsmouth who travelled to Syria to fight as jihadis

The last of a group of young men who travelled from Portsmouth to fight with Islamic State (IS) has died, it was claimed.

Assad Uzzaman, 25, was one of five men who styled themselves the Britani Brigade Bangladeshi Bad Boys and travelled to Syria to fight as jihadis.

The group were spotted on camera walking through Gatwick airport in October 2013 as they headed for the war-torn country.

Of the group four are now dead and a fifth, Mashudur Choudhury, is serving a prison term in the UK.

A sixth man, Ifthekar Jaman, was one of the first Britons to join IS and encouraged others to fight with him in Syria. He was killed in December 2013.

Uzzaman - Jaman's cousin - is thought to be the 50th Briton killed while fighting in Syria and Iraq.

His death was reported by Shiraz Maher, a senior research fellow at the International Centre for the Study of Radicalisation (ICSR) at King's College in London, which monitors social media accounts of alleged jihadists.

He said: "The last of the Portsmouth cluster of fighters with Islamic State, Assad Uzzaman (Abu Abdullah) has died."

Mr Maher said the exact nationality of one of those on the ICSR's database was unclear, so the milestone of 50 Britons may be under dispute.

Uzzaman travelled to Syria almost two years ago with four others from Portsmouth - Choudhury, 31, Muhammad Mehdi Hassan, 19, Mamunur Mohammed Roshid, 24, and Muhammad Hamidur Rahman 25.

Ifthekar Jaman, the first of the group to die, told the BBC's Newsnight just weeks before his death that he was engaged in jihad, or holy war, to help set up a state based on Islamic religious law. He told the BBC he posed no threat to the UK and had no plans to return.

Rahman is thought to have died in July last year while Roshid was killed in October. Hassan also died in October, fighting in Kobani, Syria.

Choudhury, a father of two, was jailed for four years last December for travelling to Syria to attend a terrorist training camp.

During his trial the jury heard he used Skype to send messages to Jaman, and that in a series of text messages Choudhury exchanged with his wife she told him: "Go die in battlefield. Go die, I really mean it just go. I'll be relieved. At last. At last."