UK police have foiled eight major plans for terror attacks across the UK in the last 12 months - the majority of which have been in London.
That's according to Metropolitan Police Commissioner Sir Bernard Hogan-Howe who is in charge of the capital's 32,000 strong force - 90 per cent of which are unarmed.
Following major terror attacks in France, Germany and Brussels which have killed hundreds of citizens, he said terror remains a hugely complex challenge and the London threat level remains at "severe".
"If it was us today, I would suspect a very difficult challenge. I can only talk about our system and at the moment we're okay but tomorrow, who's to say? I think it's a very difficult problem," he said.
The comments come as UK police appeal for information on two men suspected of attempting to abduct a Royal Airforce Serviceman and drag him into a waiting car with a knife in Norfolk this week in an attack that echoes the killing of Lee Rigby three years ago.
While the victim managed to fight them off, Detective Superintendent Paul Durham believes the target may have been significant and wants the public on high alert after the men mysteriously disappeared.
"It is probable that there would have been a degree of planning involved and in order to achieve this, it is quite possible that there was at least one other person involved," he said.
It comes as Europe has been left reeling over a wave of attacks in France and Germany which saw an 86-year-old priest have his throat cut at the altar of a provincial church by 19-year-old Adel Kermiche who was quickly radicalised and under police curfew.
Sir Bernard said the main challenge for police is to capture suspects as they move from a "priority four" risk of committing an attack up to a "priority one" which can happen in a very short space of time.
"There are indicators that people are moving from 'it's a nice idea', to 'I'm going to do it'. And what we have to make sure is that our coverage of those people is as good as it could be to spot that moment because of course they cannot be convicted of a thought."
"You could have evil thoughts and that's not a criminal offence. It's when they move to action that's when we have to take our own action."
t's an almost impossible challenge for intelligence, security and police forces who have changed the way they work together post 9/11 in an environment where the usual rules according to criminality don't apply.
"What we now see with this kind of attack is that the people who carry them out are not deterred by the chance of detection. So if they're going to die in the process of killing other people they cannot be deterred by going through a court process.
"Most people do not want to get caught murdering other people because they don't want to go to court and go to prison. If you have a suicide attacker they don't care, which means that we have to act far more quickly."
So far more than 12,000 people have travelled to Syria from Europe as foreign fighters or in a humanitarian capacity, 800 of whom have come from the UK. Sir Bernard said two thirds of those from the UK were previously unknown to police, raising huge challenges in terms of how to stop the flow.
Despite criticism the government's counter-terrorism strategy known as, Prevent could "end up promoting extremism, rather than countering it," he said the imperfect system is the best one yet.
"It's got it's risks. It's iterated over the years and may need to iterate again but broadly ... I don't think I've seen a better one yet in the world."
Despite the challenges and the threat level currently sitting at "severe" the UK's top cop remains adamant London is one of the "safest cities in the world" with military and security forces having gleaned insights from their European counterparts in the last 18 months.
"We all have to be clear, that type of attack is very challenging and the first few minutes there is always a danger of serious injury or death.
"Our ability to respond quickly, in force, and to respond with flexibility to something we didn't anticipate is the priority we have to achieve."