A British teenager who killed three young girls at a Taylor Swift-themed dance event was jailed for at least 52 years on Thursday, for an attack Prime Minister Keir Starmer called one of the most harrowing moments in Britain's history.

A British teenager on Thursday repeatedly interrupted the start of his sentencing for murdering three young girls at a Taylor Swift-themed dance event last July, shouting from the dock that he was unwell before being removed.

A UK judge is due on Thursday to sentence a teenager who brutally murdered three young girls in a stabbing spree last year that sparked the country's worst riots in over a decade.

The British navy said Wednesday that is ramping up measures to protect its waters from secret Russian operations after identifying a Russian spy vessel in UK waters for the second time in weeks.

The Royal Navy has been monitoring a Russian spy ship after it was spotted around UK waters earlier this week, the defence secretary has told MPs. John Healey said the vessel, Yantar, was used for gathering intelligence and mapping the UK's critical underwater infrastructure.

Britain said it monitored a Russian spy ship in the English Channel in recent days and would strengthen its response to secret operations by Russian ships and aircraft in an effort to protect undersea cables.