British police arrested four men on Friday on suspicion of spying for Iran following an investigation into their suspected surveillance of London's Jewish community.
Detectives said one of the men was Iranian, while three had dual British-Iranian nationality, and they had been taken into custody after being arrested in Barnet, north London, and in Watford, a town 15 miles (24 km) north of London.
The arrests were part of a "long-running investigation," police said, suggesting the men's suspected surveillance of Jewish sites and individuals pre-dated the U.S. and Israeli bombardment of Iran, which started last Saturday.
British lawmakers and the domestic spy agency have long warned of threats posed to Britain by Iran, while Australia has also linked antisemitic attacks to Tehran.
"Iran is the biggest state sponsor of terrorism globally, and sadly, that is in effect in our own society as well," Deputy Prime Minister David Lammy told the TV breakfast show Good Morning Britain when asked about the arrests.
Searches are continuing
Police said the four detained men were aged between 22 and 55. Six others were also arrested on suspicion of assisting an offender, and police said searches were ongoing.
Speaking about the current Iranian conflict on Thursday, Prime Minister Keir Starmer warned that people would use it to divide the country.
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British Prime Minister Keir Starmer and wife Victoria at the scene of an antisemitic attack on a synagogue in Manchester
(Photo: Phil Noble/Pool Photo via AP)
"The government is reaching out to communities across the United Kingdom - Jewish and Muslim alike - making sure communities and places of worship have appropriate, protective security in place," he told a press conference.
Illustrating the threat from Iran, Britain's MI5 spy boss said that over two years from 2022-2024, his service and British police had responded to 20 Iran-backed plots to kidnap or kill British nationals or individuals based in Britain who were regarded by Tehran as a threat.
Britain also recorded a 4% rise in antisemitic incidents in 2025, making it the second-worst year on record, a charity said. Two men were killed last October during an attack on a synagogue in the northern English city of Manchester.
Last year, police arrested five men, four of them Iranian, over a suspected plot to target specific premises. British media reported that the Israeli embassy in London had been a target.