An associate of the man who killed two people in a brutal terrorist knife attack on the London Bridge was arrested on Saturday to prevent an apparent copycat attack.

Nazam Hussain, 34, was involved in a terrorist Islamic State cell along with Usam Khan, whose Friday knife attack ended in his death by police gunfire. Both men were jailed along with others in 2012 after being charged with plotting to attack several high-profile targets in London, including the stock exchange and Westminster Abbey.