Seven people have been arrested in raids in London, Birmingham and elsewhere linked to the Westminster terror attack, police have revealed.

Mark Rowley, the Met's senior anti-terror officer, said six addresses were raided overnight.

He spoke as MPs were returning to Parliament in a show of defiance.

Mr Rowley revised the death toll down from five to four - the attacker, Pc Keith Palmer, who he stabbed, and a woman in her mid 40s and a man in his mid 50s, who were mown down as the terrorist sped across Westminster Bridge in his car.

He said 29 people had been treated in hospital with seven people in a critical condition.

At the scene of one of the police raids, a flat in Hagley Road, Birmingham, one witness told the Press Association: "The man from London lived here."

Mr Rowley said it was still his belief the attacker worked alone and was inspired by "international terrorism", adding that there was no specific information to suggest any further threat to the public.