Britain's domestic spy chief Ken McCallum warned of the dangers posed by Russia and Iran as well as growing concern about al Qaeda and Islamic State in his annual update on the threats faced by Britain on Tuesday.
Here are some of the main issues raised by McCallum, the Director General of the Security Services known as MI5, in his speech at London's Counter Terrorism Operations Centre.
RUSSIA
McCallum said since Russia's invasion of Ukraine, more than 750 Russian diplomats had been expelled from Europe, with "a great majority of them spies".
He said this had put a big dent in the Russian intelligence services' capability, and that this was being maintained by denying diplomatic visas to those Britain and allies considered Russian spies.
"Kick them out, keep them out," he said.
Instead, Russian state actors had turned to proxies including private intelligence operatives and criminals from Britain and other countries to do "their dirty work", but this had diminished the professionalism of their operations and made them easier to disrupt.
IRAN
Since January 2022, MI5 and British police had responded to 20 Iran-backed plots "presenting potentially lethal threats to British citizens and UK residents", McCallum said, adding that since the death of Masha Amini in Iranian police custody in September 2022 there had been "plot after plot".
Like Russia, Iran was also using criminal proxies from drug traffickers to low-level crooks, he said.
CHINA
China still remained a significant risk, particularly its threat to obtaining sensitive information from businesses and academia, he said.
However, he said China was "different" and because of Britain's multi-layered complex relationship with Beijing, it required a more nuanced approach.
"The UK-China economic relationship supports UK growth, which underpins our security. And there are also risks to be managed," he said. "The choices are complex and it rightly falls to ministers to make the big strategic judgments on our relationship with China."
