Read more: Tributes paid to hero police officer killed in London terrorist attack

The policeman who died earlier today has been named by Scotland Yard as Keith Palmer.

Mark Rowley, assistant commissioner for specialist operations at the Metropolitan Police, confirmed Mr Palmer was the officer who died after being stabbed by a terrorist outside the House of Commons.

Mr Palmer, 48, was a husband and father who had served as a police officer for 15 years.

Mr Rowley also revealed a fifth person had died and that about 40 people had been injured in the attack in central London.

Read more: Terror at Houses of Parliament as knifeman kills police officer and mows down pedestrians 

Read more: Prime Minister condemns ‘sick and depraved’ terrorist attack