Amess's murder has shocked Britain's political establishment coming five years after another lawmaker was murdered, prompting calls for increased safety for members of parliament.
Ali Harbi Ali, 25, has been charged with murder and preparing acts of terrorism.
"We will submit to the court that this murder has a terrorist connection, namely that it had both religious and ideological motivations," Nick Price, Head of the Crown Prosecution Service Special Crime and Counter Terrorism Division.
"He has also been charged with the preparation of terrorist acts. This follows a review of the evidence gathered by the Metropolitan Police in its investigation."
Ali, the son of an ex-media adviser to a former prime minister of Somalia, is due to appear at London's Westminster Magistrates' court later on Thursday.
Matt Jukes, London police's Assistant Commissioner for Specialist Operations, said the charges followed extensive work by detectives.
"There has been considerable speculation in the media about the background, history and motivation of the man now charged," he said.
"I understand the huge level of public interest in this case, but now a charge has been brought, it is vitally important that everyone exercises restraint when commenting on it publicly, to ensure future court proceedings are not prejudiced in any way."
He said no other arrests had been made and they were not looking for any other people in connection with the murder.
On Wednesday, October 20, British interior minister Priti Patel said the terrorism threat level to members of parliament was now deemed substantial, which means an attack is considered likely. – Rappler.com