Terror arrests come amid increased security service warnings about Iranian activity on British soil

These are two separate and unrelated investigations by counter-terror officers.

But the common thread is nationality - seven out of the eight people arrested are Iranian. And that comes in the context of increased warnings from government and the security services about Iranian activity on British soil.

Last year, the director general of MI5, Ken McCallum, said his organisation and police had responded to 20 Iran-backed plots presenting potentially lethal threats to British citizens and UK residents since January 2022. He linked that increase to the ongoing situation in Iran's own backyard.

"As events unfold in the Middle East, we will give our fullest attention to the risk of an increase in - or a broadening of - Iranian state aggression in the UK," he said. The implication is that even as Iran grapples with a rapidly changing situation in its own region, having seen its proxies, Hezbollah in Lebanon and Hamas in Gaza, decimated and itself coming under Israeli attack, it may seek avenues further abroad.

The government reiterated this warning only a few weeks ago, with security minister Dan Jarvis addressing parliament. "The threat from Iran sits in a wider context of the growing, diversifying and evolving threat that the UK faces from malign activity by a number of states," Jarvis said.

"The threat from states has become increasingly interconnected in nature, blurring the lines between: domestic and international; online and offline; and states and their proxies. "Turning specifically to Iran, the regime has become increasingly emboldened, asserting itself more aggressively to advance their objectives and undermine ours." Read more:Anybody working for Iran in UK must register or face jail, government announces As part of that address, Jarvis highlighted the National Security Act 2023, which "criminalises assisting a foreign intelligence service.