British airstrikes on ISIS fanatics could last for three years starting tomorrow if MPs back military action in a special Parliamentary session.

David Cameron held a War Cabinet this afternoon on the Government's plan to target Islamist fighters in northern Iraq and received its backing.

MPs will vote around 5pm tomorrow evening on a Commons motion authorising British involvement in US-led bombing raids. It means RAF fighter jets could be over Iraq within hours of the vote.

Defence Secretary Michael Fallon has warned that the campaign against ISIS in Iraq was for a 'long haul' of 'two of three years' at least. Mr Cameron’s official spokesman later admitted the action could take a ‘very considerable time’.

It came after the Iraqi government revealed that it had received 'credible' intelligence that ISIS militants are planning to launch attacks on subway systems in Paris and New York.

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Tornado jets took off from RAF Marham, Norfolk, this afternoon as the Government prepared the country for military action against ISIS

Tornado jets are likely to launch their airstrikes from RAF bases in Akrotiri in Cyprus where they have been flying reconnaissance missions over northern Iraq since last month

Fuel drop tanks for Tornado jets at RAF Marham, Norfolk, pictured today as jets from the base prepare for deployment to Cyprus to help with the possible air strikes against jihadist extremists in Iraq

The country’s Prime Minister Haider al-Abadi, speaking in New York, said the plot been hatched by foreign fighters belonging to ISIS in Iraq. Asked if the attacks were imminent, he said: 'I'm not sure.'

He said that he received the information from intelligence officials based in Baghdad earlier this morning.

It comes amid soaring public support for airstrikes following the beheadings of British hostage David Haines. Britons are now split two to one in favour of bombing ISIS, according to a poll released today.

A third of the public also support sending ground troops in to tackle the fanatics, according to the pollsters YouGov – although almost half of Britons are against boots on the ground.

All three Westminster party leaders have signalled their support for British airstrikes on ISIS, almost guaranteeing that Parliament will authorise military action tomorrow.

Mr Fallon, speaking in tomorrow's issue of The House magazine,said Britain had to 'face up to this' threat from ISIS or face attacks in Britain.

He said: 'This has to be planned, it has to be sustained. This is going to be a long drawn campaign which we have to be careful, methodical and measured about.'

Mr Fallon added: 'But equally there’s a determination right across Nato to tackle ISIL. Because if we don’t, it comes back on us.”

He added: “John Kerry has estimated two to three years, that looks like a long haul to me. But we have to face up to this.'

The Prime Minister's official spokesman said Mr Cameron was 'not putting a timeframe on our approach and our engagement' in Iraq.

He said: ‘It will take time, a very considerable time to achieve the objectives in respect to ISIL – not least because there is a process of developing the [Iraqi and Kurdish forces’] abilities and capacities so they are more able to hold terrain.

‘The Prime Minister has said that this engagement by the international community is going to take a very considerable time.’

He said there would be no ground combat forces – but this does not mean special forces or rescue missions were banned.

Defence Secretary Michael Fallon (right) and Chief of the Defence Staff Nick Houghton - the head of the Army - arrive in Downing Street for today's special war Cabinet

The public has swung behind British airstrikes on ISIS over the past six weeks, according to the pollsters YouGov

THE COMMONS WAR MOTION AUTHORISING AIRSTRIKES ON ISIS British bombing raids on ISIS could begin within hours of MPs voting on a special 'war motion' tomorrow evening. The motion, laid before the Commons this afternoon, states: 'This House condemns the barbaric acts of ISIL against the peoples of Iraq including the Sunni, Shia, Kurds, Christians and Yazidi and the humanitarian crisis this is causing; 'Recognizes the clear threat ISIL pose to the territorial integrity of Iraq and the request from the Government of Iraq for military support from the international community and the specific request to the UK Government for such support; 'Further recognizes the threat ISIL poses to wider international security and the UK directly through its sponsorship of terrorist attacks and its murder of a British hostage; 'Acknowledges the broad coalition contributing to military support of the Government of Iraq, including countries throughout the Middle East; 'Further acknowledges the request of the Government of Iraq for international support to defend itself against the threat ISIL poses to Iraq and its citizens, and the clear legal basis that this provides for action in Iraq; 'Notes that this motion does not endorse UK air strikes in Syria as part of this campaign, and any proposal to do so would be subject to a separate vote in Parliament; 'Accordingly supports Her Majesty’s Government, working with allies, in supporting the Government of Iraq in protecting civilians and restoring its territorial integrity, including the use of UK air strikes to support Iraqi, including Kurdish, security forces’ efforts against ISIL in Iraq; 'Notes that Her Majesty’s Government will not deploy UK troops in ground combat operations; 'Offers its wholehearted support to the men and women of Her Majesty’s armed forces.' Advertisement

Deputy Prime Minister Nick Clegg this morning claimed it would be 'extraordinary' if Britain did not join the military alliance against ISIS. Mr Clegg said: 'Are we the United Kingdom going to play our part or not?

'Are we at least going to play our part, provide our bit of the jigsaw as part of the huge international Coalition that has been assembled against ISIL?

'It would be quite extraordinary if after all we've seen we were to say, 'you know what we're going to wash our hands of all of this and let other people do our dirty work for us'

It comes after Mr Cameron told the United Nations last night that the UK was ready to play its part in confronting 'an evil against which the whole world must unite'.

In what amounted to a rallying cry to MPs to back military action when Parliament is recalled tomorrow, the Prime Minister warned that Britain must not be so 'frozen with fear' of repeating the mistakes of the Iraq War that it fails to take on the 'psychopathic, murderous, brutal' jihadis.

Amid speculation that RAF planes could join US and French allies in bombarding IS targets as early as this weekend, Mr Cameron declined to discuss when the operation might begin or how long it would last, but acknowledged that it could take 'quite a long time'.

He said he was 'confident' of receiving support from the three major parties in the parliamentary vote, avoiding the embarrassment of a repeat of last year's defeat over plans to bomb Syria.

Speaking to reporters in New York, Mr Cameron made clear that he envisages British warplanes joining coalition air strikes within Iraq, after receiving a request for military help from the country's new prime minister Haider Abadi, and stressed that there would be no 'boots on the ground'.

Islamic State - also known as Isis or Isil - posed a 'clear and present danger to the United Kingdom' and the Baghdad government's invitation gave 'a clear legal base' for British military action, he said.

But he did not rule out later extending operations to IS strongholds in Syria - targeted by the US and its allies for the first time early on Tuesday - saying that this would happen only after a separate debate and vote in Parliament.

In a speech to the United Nations General Assembly, Mr Cameron acknowledged the wariness felt by many in the international community over military action in Iraq, following the decade of violence which followed the US-led invasion of 2003.

But he said it was vital to 'learn the right lessons - Yes to careful preparation; no to rushing to join a conflict without a clear plan'.

Mr Cameron warned: 'We must not be so frozen with fear that we don't do anything at all.

'Isolation and withdrawing from a problem like Isil will only make things worse.

'We must not allow past mistakes to become an excuse for indifference or inaction.'

Action against IS should be 'comprehensive, intelligent and inclusive', working with partners in the region, potentially including Iran - whose president Hassan Rouhani he met for historic talks at the UN.

And he added: 'We should be uncompromising, using all the means at our disposal - including military force - to hunt down these extremists.'

The struggle with extremism must be waged not only against IS in Iraq and Syria, but also against Boko Haram in Nigeria, Al-Shabaab in Somalia, Ansar Al-Sharia in Libya and al-Qaida in Yemen, Mr Cameron said.

While the threat would not be best solved by Western ground troops 'directly trying to pacify or reconstruct Middle Eastern or African countries', there was a place for the military in training, advising and supporting humanitarian missions, as well as in responding to the Iraqi government's request to the UN for support.

'My message today is simple,' he told the UN. 'We are facing an evil against which the whole world must unite. And, as ever in the cause of freedom, democracy and justice, Britain will play its part.'

Mr Cameron's comments came after US president Barack Obama issued a plea to the international community to come together to 'dismantle this network of death'.

He said the world should be 'uncompromising, using all the means at our disposal - including military force - to hunt down these extremists'

TORIES SAY ATTACKS ON SYRIA SHOULD NOT BE RULED OUT David Cameron is facing calls from some Conservative MPs to leave open the option of British air strikes on Islamic State forces in Syria. As MPs began heading back to Westminster for tomorrow’s emergency Commons vote on military action against IS in Iraq, senior Tories said that it may not be sufficient to defeat the militants. Mr Cameron has deliberately restricted Britain’s involvement to Iraq in part to secure the support of Labour, which has raised concerns about extending air raids into Syria without specific authorisation of the United Nations Security Council. The Prime Minister is desperate to avoid a repeat of last year’s Commons vote on military action when Labour combined with Tory rebels combined to inflict a damaging defeat on the Government. Conservative backbencher Bob Stewart - a member of the Commons Defence Committee and a former British commander in Bosnia - said that IS had to be defeated in its birthplace in Syria. 'You have got to go to the eye of the octopus,' he said quoting the US civil rights activist Stokely Carmichael. He added: 'And the eye of the octopus isn’t necessarily in Iraq, it is in Syria.' Former defence minister Sir Gerald Howarth added: 'If you don’t attack their bases in Syria, then clearly you are not addressing it,” he told The World at One. “One will be left with the taste in the mouth that we are leaving it to the Americans to do the dirty end of the job.' Advertisement

Speaking to the General Assembly, Mr Obama said that IS understood only 'the language of force' and called on those who have joined up to fight with the group to 'leave the battlefield while they can'.

The president condemned atrocities against women and religious minorities in IS-controlled areas and described the beheading of hostages including British aid worker David Haines as 'the most horrific crimes imaginable'.

'No God condones this terror. No grievance justifies these actions. There can be no reasoning - no negotiation - with this brand of evil,' said Mr Obama.

'The only language understood by killers like this is the language of force. So the United States of America will work with a broad coalition to dismantle this network of death.'

Addressing the fears expressed by the family of British hostage Alan Henning, who have said UK air strikes could increase the danger to his life, Mr Cameron told reporters: 'It's a desperate situation, but let's be clear about two things.

'One is that we are dealing with psychopathic, murderous, brutal people who will stop at nothing to carry out dreadful acts on these hostages.

'And secondly, it's very important that we do the right thing as a country and we stick to the path that I set out some weeks ago about having a comprehensive strategy including all the elements at our disposal - humanitarian aid, diplomacy and also, where appropriate, military action. That's the way in which we are proceeding.'

Asked whether wanted to see justice served on the Briton, nicknamed 'jihadi John', believed to be responsible for three beheadings, Mr Cameron replied: 'I'm not sure I can describe in words what I'd like to happen to him. He should see justice one way or another.'

Mr Cameron backed a UN resolution tabled by the US to stem the flow of foreign fighters enlisting in conflicts overseas, including by withholding passports and freezing assets.

Addressing the Security Council, the Prime Minister said IS had behaved with 'medieval barbarity'.

And he added: 'One of the most disturbing aspects is how this conflict is sucking in our own young people, from modern, prosperous societies.

'The threat to our security from foreign fighters is far greater today that it has ever been in previous conflicts.'

Foreign Secretary Philip Hammond arrives in Downing Street today ahead of tomorrow's Commons vote on airstrikes against ISIS

The 12,000-plus recruits - including 500 Britons - who have flocked from around the world to join Islamic State were 'a small army, brainwashed and turned into fanatics determined to harm their own countries', he said.

Deputy Prime Minister Nick Clegg and Labour leader Ed Miliband each confirmed that they would be backing the PM's call for military action in tomorrow's vote.