Manchester attack: Police fear Salman Abedi could have made a second bomb

Officers discover enough materials 'to build two or three bombs' at suicide bomber's home

Fears grow he may have learnt sophisticated bomb-making techniques in Libya or Syria

Police fear the Manchester suicide bomber may have made a second bomb, after raids on his home uncovered a stash of chemical explosives, it has been reported.

Officers discovered evidence of a "working bomb factory" at Salman Abedi’s address, according to The Telegraph, raising fears he may have distributed further explosive devices to other radical extremists.

It comes after The Independent revealed on Thursday police and security services had found bomb-making materials as they conducted raids across the country, which they feared could be primed for imminent attacks.

One suspect device was blown up in a controlled explosion and security sources said on Wednesday there was a real possibility other materials were yet to be found.

A security source told The Telegraph: "The worry is there was enough to build two or three bombs and we can't rule that out."

It comes as police worked to establish Abedi’s final movements after it emerged he flew back to Britain via Turkey and Germany just four days before carrying out his attack.

German intelligence services said Abedi flew to the city via Istanbul and Düsseldorf, although questions remained over the 22-year-old’s previous location.

France’s interior minister previously said Abedi had visited Libya “and then most likely gone to Syria”, although no concrete evidence has emerged to support the claim.

Analysts pointed out that Turkey is a frequent transit point for Isis fighters crossing the border to and from Syria by land.

Former Metropolitan Police officer, David Videcette said Abedi had likely spent months practising how to assemble the device while he was abroad.

He told The Telegraph: "This is not something you can just put together by reading a book or watching a YouTube video. He will have spent time at a camp somewhere, possibly in Libya, being shown how to do it. But once you have the skills and the materials, assembling the device itself can be done fairly quickly."

The number of arrests in the UK ticked up to eight on Thursday as police continued to work to uncover a UK network of extremists working with Abedi.