The head of the Armed Forces yesterday warned Islamic State jihadis were 'moving in migrant flows, hiding in plain sight'.
Air Chief Marshal Sir Stuart Peach, chief of the defence staff, said foreign militants were being moved from their shrinking stronghold in Iraq and Syria.
And he warned copycat terrorists are now 'popping up all over the world' as propaganda spreads through social media.
In his first major speech since taking up the role in July, Sir Stuart said Britain also faced an 'era of competition' with other states – and that Russia was not playing by the rules.
He continued: 'I would argue that all this combines to [be] a threat and a risk to our way of life and an element of a sense of uncertainty and, indeed, I would use the word danger.'
Speaking at the Royal United Services Institute, he said: 'We face a potential network of combat experienced terrorists.'
He added that the UK was playing a 'full part' in the campaign against IS, which is also known as Daesh. But he said: 'I worry about the global reach of Daesh as an idea, using the internet ... using social media.
'They are losing territory rapidly, foreign fighters are being killed and displaced but they are moving in migrant flows, hiding in plain sight.'
Terrorists are able to destroy their passports and change their identities using forged documents to travel to other countries, he warned, adding: 'How we manage identity in a world where people are deliberately trying to destroy their identity documents and move in migrant flows – it is a very important subject.'
Sir Stuart also warned Britain should be 'really worried' that the international consensus-based approach to peace and security, which emerged after the Second World War, was now challenged by states such as Russia.
The UK is now in a 'strategic state-on-state era of competition' which requires us to respond to propaganda, hybrid warfare and cyber attacks, he said.
His comments follow the Russian incursion in Ukraine and worries that Moscow influenced the US presidential election won by Donald Trump by allegedly hacking email accounts linked to his rival Hillary Clinton.
'There's no doubt, it's not a secret, that Russia is using cyber as a part of [its] power,' Sir Stuart said. 'This is in direct competition with our approach to sustain the rules-based order.' He continued that he was 'happy to talk to Russia', but that this 'does not mean business as usual'.
He said he had visited the country last year to talk about deconfliction as Russia sent warplanes close to UK airspace.
Sir Stuart described the threat of cyber activities for commercial gain and state advantage as a 'worrying trend', especially as it is often difficult to find out who is responsible.
Courtesy Daily Mail