Manchester attack: UK terror threat raised to critical

It comes after 22 people were killed, including an eight-year-old girl, and 59 were injured in a bombing at Manchester Arena on Monday night.

The change in terror threat comes after investigators were unable to rule out whether suspect Salman Abedi was part of a group, the prime minister said.

Meanwhile, Olivia Campbell (15), has been confirmed as the fourth victim of the incident by her mother.

Eight-year-old Saffie Roussos, Georgina Callander (18) and John Atkinson (28) were also killed.

The prime minister said soldiers would be placed in key public locations to support armed police in protecting the public. These include Buckingham Palace, Downing Street, embassies and the Palace of Westminster.

Military personnel may also be seen at other events over the coming weeks, such as concerts, Mrs May said.

The highest threat level, which is decided by the Joint Terrorism Analysis Centre — a group of experts from the police, government departments and agencies — has only been reached twice before.