Four people have been arrested as part of a counter-terrorism investigation relating to Iran, the Metropolitan Police has said.

Police arrested one Iranian and three dual British-Iranian nationals on suspicion of assisting a foreign intelligence service.

The investigation relates to the suspected surveillance of locations and individuals linked to Jewish communities in London, the Met said.

Commander Helen Flanagan, head of Counter Terrorism Policing London, said they understand "the public may be concerned, in particular the Jewish community" and asked them to remain vigilant.

She added that the arrests, which took place around 01:00 GMT, are part of "a long-running investigation and part of our ongoing work to disrupt malign activity where we suspect it".

Speaking to ITV's Good Morning Britain shortly after news broke of the arrests, Deputy Prime Minister David Lammy said: "Iran is the biggest state sponsor of terrorism globally and sadly, that is in effect in our own society as well.

"Our intelligence services and counter-terrorism police have thwarted lots of action over the last few years," he added. He also praised the work of the security services and police.

The Community Security Trust, a charity which seeks to protect Britain's Jewish community, thanked police in a statement and added: "Security is strong across the Jewish community."

A 40-year-old and a 55-year-old were arrested at addresses in Barnet, a 52-year-old in Watford and a 22-year-old in Harrow.

Searches remain ongoing in Watford, Barnet, and an address in Wembley.

The four men were detained under the National Security Act, which was introduced in 2023 to modernise counter spying laws, combating foreign interference.

After Iran launched retaliatory strikes following the US-Israel attack at the weekend, Prime Minister Sir Keir Starmer condemned Iran's actions against "partners across the region".

"Even in the United Kingdom, the Iranian regime poses a direct threat to dissidents and to the Jewish community," Sir Keir added.

"Over the last year alone, they have backed more than 20 potentially lethal attacks on UK soil."

Six other men aged 29, 39, 42, 49 and two aged 20, were arrested at the same location in Harrow on suspicion of assisting an offender.

All 10 men have been taken into custody.

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