BORIS Johnson has called for a new drive to combat international terrorism as he made clear Brexit would not trigger a British retreat from the wider world.

In a keynote diplomatic speech, the Foreign Secretary said that blaming Western military interventions for terror only fuelled the rise of jihadism, which he said had the "addictive power of crack cocaine".

Mr Johnson said that the UK's position as Nato's second biggest contributor, its huge overseas aid budget, and extensive diplomatic reach would ensure it remained engaged globally.

Stressing how the UK needed to remain a strong international player, he said: "You can make an argument that we got things wrong in the past but retreat is not the solution.

"A retreat by Britain is exactly the wrong prescription. On the contrary, we need to be more outward looking and more engaged.

"Other countries want to see more of the UK, not less. They want to see us more involved,” declared Mr Johnson.

He issued a call for unity with Muslims around the world, who were "equally determined" to fight Islamist terror, and argued the West needed to realise that hundreds of millions of Muslims were on its side in the battle against terrorism.

His speech at the Foreign Office came as new official figures showed terror suspects were being arrested in record numbers following a dramatic surge in activity by security agencies and a flurry of attacks.

Statistics showed a total of 400 people were held on suspicion of terrorism-related offences in Britain in the year to the end of September; a rate of more than one every day.

This was the highest tally since data collection started in 2001 and a jump of 54 per cent compared with the previous year.

The Home Office said the increase was partly due to a large number of arrests made following terrorist attacks in London and Manchester.

The 400 total includes 64 arrests made in connection with the Westminster [12], Manchester [23], London Bridge [21], Finsbury Park [one] and Parsons Green [seven] attacks.

Earlier this week, Amber Rudd, the Home Secretary, disclosed that MI5 and police had now thwarted 22 Islamist plots since the murder of Lee Rigby in May 2013. This included nine which had been foiled since the Westminster atrocity in March.

On Wednesday, a 20-year-old man was remanded in custody after appearing in court accused of plotting to kill Theresa May by first detonating an explosive device to get into her Downing Street office.

Elsewhere, Gavin Williamson, the Defence Secretary, came under fire over his suggestion that Islamist fighters should be hunted down and killed.

Lord Campbell, the Liberal Democrat defence spokesman, said Mr Williamson appeared to be endorsing breaches of humanitarian law while Labour’s Dan Jarvis, a former paratrooper, said his comments were "morally, legally and practically wrong".

The Secretary of State told The Daily Mail those who were intent on bringing "destruction, death and bloodshed" onto the streets of Britain were being "hunted down" and the threat "eliminated".

He added: "A dead terrorist can't cause any harm to Britain."

Lord Campbell, the former Lib Dem leader, denounced Mr Williamson's “gung-ho” comments as “ill-considered and appear to endorse a clear breach of humanitarian law".