Man with Knife Arrested Outside Buckingham Palace Moments Before Queen Drives Past

A man with a knife has been arrested near Buckingham Palace, as Britain remains on critical terror alert amid fears Manchester suicide bomber Salman Abedi did not act alone.

The man was detained by police on The Mall just moments before the Queen passed by in a car on her way to an engagement with the Duke of Edinburgh at St Paul's Cathedral.

A picture showed the man surrounded by officers and handcuffed as he sat on the ground, while a police officer nearby held what was believed to be a large blade that had been seized.

The Metropolitan Police said the incident, at around 10.40am on Wednesday, is not believed to be terror-related. However, it comes amid heightened security and as armed soldiers prepare to guard "key locations" across London.

A witness said he saw the man surrounded by officers and handcuffed as he sat on the ground in The Mall at around 10.40am.

A police van arrived with lights flashing and drove him away.

A Scotland Yard spokesman said the man was arrested in The Mall and a knife was recovered.

Nobody was injured and police were not treating it as a terror related incident. The man has been taken to a central London police station for questioning.

The arrest happened shortly before the Queen was driven from the Palace for an engagement with the Duke of Edinburgh at St Paul's Cathedral.

They are attending a service to mark the centenary of the Order of the British Empire.