Military forces are to be deployed to various landmarks and public places around the UK.
It has been reported Buckingham Palace, Downing Street, the area around the palace of Westminster, and embassies across London will receive military support.
Up to 3,500 soldiers will be present on the streets of Britain, replacing police officers in order to free up time for them to focus on other duties, like the investigation into the Manchester Arena bombing.
The news comes after Theresa May raised the UK's terror threat level to 'critical' following the attack which killed 22 and injured around 64.
The Prime Minister said her decision was based on information which suggested Salman Abedi had not acted entirely on his own, with a "wider group of individuals" present.