- British Prime Minister warns Paris attacks 'could have happened here'
- Scale of atrocity sends security agencies 'back to the drawing board'
- Seven plots foiled in last 12 months were 'smaller' than seen in Paris
- MI5, MI6 and GCHQ to get a 15% increase in staff to tackle the threat
- Spending on aviation security will increase to double current £9million
- Theresa May insists Paris fanatics represent no-one 'and will fail'
- Labour's Jeremy Corbyn is 'not happy' about shoot to kill order in Britain
- See full coverage of The Prime Minister at www.dailymail.co.uk/pm
A terror attack on the UK was foiled in the last two and a half weeks, David Cameron revealed today as he vowed to recruit an extra 1,900 spies to counter the threat posed by ISIS terror cells in Syria.
The Prime Minister said seven deadly plots to cause havoc in the UK have been disrupted in recent months - one more than revealed by the head of MI5 on October 28.
But Mr Cameron warned that the scale and severity of the attacks in Paris which left 129 people dead were far greater than anything seen by intelligence agencies to date.
Prime Minister David Cameron, pictured in Turkey today, announced the government is going to recruit almost 2,000 more spies to counter the Islamic State threat, just days after 129 people were killed in Paris
The security and intelligence services will receive a major increase in funding in response to the ISIS threat, which has been blamed for the bombing of a Russian airliner in Egypt and the Paris attack in recent weeks.
Mr Cameron announced a 15 per cent increase in the 12,700-strong staff of the security and intelligence agencies MI5, MI6 and GCHQ with the recruitment of an additional 1,900 personnel.
Meanwhile spending on aviation security will increase to at least double the current £9million a year.
The Prime Minister said the UK was engaged in a 'generational struggle' against extremist terror.
The additional spending will help 'combat those who would destroy us and our values' and allow Britons to 'continue with our way of life we hold so dear'.
He told BBC Radio 4's Today programme: 'I have been aware of these cells operating in Syria that are radicalising people in our own country, potentially sending people back to carry out attacks.
'Our security services have stopped seven attacks in the last six months, albeit on a smaller scale.'
Downing Street later clarified that the seven attacks were 'in the last year' but refused to give details of the latest attack.
On October 28, MI5 chief Andrew Parker used a speech to reveal: 'With our partners, we have thwarted six attempts at terrorist attacks in the UK in the last year, and several plots overseas.'
Plans for how to respond to a Paris-style marauding gun attack have been reviewed in the wake of the Paris atrocity, which marked a change in the nature of ISIS plots.
'Those attacks in Paris, that could have happened in Belgium, that could have happened in Denmark, it could have happened in Sweden, it could happen here,' Mr Cameron said.
'We stand in total solidarity with France after the appalling attacks in Paris.'
British security services had been preparing for an attack involving gunmen targeting public areas with large groups of people, but not spread across such a large area with simultaneous attacks on cafes, restaurants, a football stadium and concert hall.
Dozens of elite SAS officers are on patrol in busy town centres and shopping centres in the UK, while the Army is on standby to provide an emergency response.
Security officials say the key to minimising the number of casualties in a gun attack in multiple places is to hit the extremists 'hard and early'.
Th SAS have been issued with orders to shoot terrorist attackers on sight. British intelligence experts are alarmed by the fact the Paris killers all wore suicide bomb vests.
Mr Cameron said: 'Whenever anything like this happens you have to go right back to the drawing board and work out what more steps we need to do to try to keep ourselves safe.'
Further evidence of the changing nature of the threat emerged yesterday when it was claimed ISIS is using the PlayStation 4 network to recruit and plan attacks because it's 'more secure than WhatsApp'.
In Belgium, which appears to be at the heart of the terror plot, officials believe that terrorists are using consoles to communicate.
Belgian Minister of Home Affairs Jan Jambon said intelligence agencies have discovered evidence of jihadis using the games consoles to communicate with a special, hidden recruitment channel.
He told HNL.be: 'Playstation 4 is even more difficult to monitor than WhatsApp.'
ISIS fanatics are also said to be using a 'cyber caliphate' - protected by their own encryption software - where they plan their next attacks.
Security has been beefed up in UK cities and ports as Britons were urged to remain vigilant, although the terror threat level has not been changed from the second-highest 'severe' rating.
Mr Cameron urged people to continue to go about their lives in the normal way. Asked if we took his own children to the friendly football match between England and France at Wembley tomorrow night, the Prime Minister said: 'Yes I would. I think it's very important that we carry on our lives. What these terrorists want to do is change our way of life.
'In a free society you never have 100 per cent security,' he added. 'Remember that our freedom depends on showing resolve and carrying out with our way of life.'
Mr Cameron is in Turkey for a meeting of G20 leaders where the agenda has been dominated by the ISIS threat.
The UK Prime Minister will hold talks with Vladimir Putin as Western allies try to persuade the Russian president to co-operate in the international struggle against ISIS.
Downing Street sources said the Prime Minister hopes to reassure Mr Putin that Russia's interests will be 'protected' in the transition to a new settlement in Syria after the departure of president Bashar Assad, a close ally of Moscow.
Mr Cameron said: 'The disagreement is we think Assad should go at once, Russia has taken a different view. We have to find a settlement where Assad leaves and there is a government that can bring Syria together.'
It has emerged Iraqi intelligence warned countries in the US-led coalition against ISIS, including France, of an imminent assault the day before the Paris attacks.
But the Iraqi dispatch provided no details on when or where the attack would take place, and a senior French security official described it as the kind of warning French intelligence gets 'all the time' and 'every day'.
Last night France launched 'massive' air strikes on the terror group's de-facto capital in Syria, destroying a jihadi training camp and a munitions dump in the city of Raqqa, where Iraqi intelligence officials say the attacks on Paris were planned.
Twelve aircraft including 10 fighter jets dropped a total of 20 bombs in the biggest air strikes since France extended its bombing campaign against the extremist group to Syria in September, a Defense Ministry statement said.
The jets launched from sites in Jordan and the Persian Gulf, in coordination with U.S. forces.
On the sidelines of the G20 summit in Turkey on Sunday, France's Foreign Minister Laurent Fabius said his country was justified in taking action in Syria.
'It was normal to take the initiative and action and France had the legitimacy to do so. We did it already in the past, we have conducted new airstrikes in Raqqa today, Fabius said. 'One cannot be attacked harshly, and you know the drama that is happening in Paris, without being present and active.'
However, Britain is not taking part in the action in Syria because MPs have so far refused to authorise the extension of airstrikes in neighbouring Iraq.
Mr Cameron has repeatedly made clear he believes it makes no sense not to extend the strikes across a border which ISIS itself does not recognise.
He said: 'I support the action in Syria. ISIL does not recognise a border between Iraq and Syria and neither should we. I need to build the argument. I need to take it to Parliament.
'Of course I think the British military would bring great effect to what's happening in Syria.'
But he said he would only push the issue to a vote if he was sure he could win, to prevent damage to Britain's reputation on the world stage.
'I will build the case but in the end Parliament must decide. I have made the promise to Parliament as previous prime ministers have done.'
France's ambassador to the UK Sylvie Bermann said it would be 'appreciated' if the RAF carried out raids in Syria alongside the French.
She told Sky News: 'It is difficult to comment because it is not only a Government decision but they have decided to consult with the Parliament. If they do participate like us, of course we will appreciate (it) because we have always fought side by side but it is their decision.'
She added: 'We have to fight side by side if we want to defeat terrorism.
But Labour leader Jeremy Corbyn has vowed to oppose any extension of British involvement, calling for a 'peaceful' solution to the conflict. He warned that increased military action was not the solution to the crisis.
He told ITV's Lorraine: 'Does the bombing change it? Probably not. The idea has to be, surely, a political settlement in Syria, very difficult to achieve.
'There are some signs that the talks over the weekend have made some progress - Iran, Russia, USA, European Union, around a table together with all the regional governments, particularly Turkey is key.
'But also, who's funding ISIS, who is arming ISIS, who's providing safe havens for ISIS to get there.
'You have to ask questions about the arms that everyone has sold in the region, the role of Saudi Arabia in this, I think there are some very big questions and we have to be careful.
One war doesn't necessarily bring about peace, it often can bring yet more conflict and more mayhem and more loss.'