The brother of the Manchester bomber knew he was going to carry out the atrocity more than a month ago, Libyan police claimed last night.

Engineering student Hashem Abedi was being interrogated last night in Tripoli over claims he helped his older brother Salman build the suicide vest.

The brothers’ father was also arrested in Libya yesterday.

Hashem, 20, has confessed to knowing about the attack when he visited his suicide bomber brother’s Manchester home in April, Libyan counter-terrorism officers said.