Following the beheading by the Islamic State of Iraq and Syria (ISIS) of British aid worker David Haines, UK Prime Minister David Cameron immediately stepped up plans to back US military action in Iraq and Syria.

Haines was working for Acted, an NGO, as a logistics officer in a refugee camp in Atmeh, a Syrian village near the Turkish border, when he was abducted last year.

The killing of the 44-year-old follows the ISIS murders of two US journalists, James Foley and Steven Sotloff. As with the US victims, ISIS released a video of Haines being killed and threatened to kill a second British hostage, a taxi driver from Greater Manchester, Alan Henning. While taking part in an aid convoy to Syria to deliver medical equipment, Henning was seized by masked gunmen after crossing the Turkish border and separated from his friends.

On Sunday morning, Cameron convened a meeting of the government’s emergency Cobra committee, including representatives from the Foreign and Commonwealth Office, the Ministry of Defence, and the Home Office.

Using Haines’ death as the casus belli, Cameron is preparing to back military strikes in Iraq and Syria, with those in his government who have cautioned against the implications of such action publicly rebuked.

Last week, Foreign Secretary Philip Hammond told a press conference in Berlin: “There is a qualitative difference between any proposition of air strikes in Syria and such an activity in Iraq. The legal, technical and military differences make the proposition of air strikes an order of magnitude more complicated in Syria.”

Following a meeting with German Foreign Minister Frank-Walter Steinmeier, Hammond said, “Let me be clear: Britain will not be taking part in any air strikes in Syria. We have already had that discussion in our parliament last year and we won’t be revisiting that position.”

He was immediately overruled by a spokesman for Cameron, who said nothing was ruled out and that Britain would work with the US and “other regional partners on the ground.”

According to the pro-Conservative Party Daily Telegraph on Monday, Cameron will recall parliament to put forward the government’s stance on Iraq and Syria next week, following the Scottish referendum vote on independence, scheduled for Thursday. The newspaper reported that following the referendum poll, Cameron will “attend the [United Nations] General Assembly in New York on Tuesday and Wednesday, at which he will outline plans to combat Islamic State in Syria … MPs have been told to expect to be recalled on the Thursday after the UN session.”

Domestic political calculations constitute a major factor in the shift of the Cameron government on Britain’s participation in another war in Iraq and air strikes in Syria. The Haines video was released in the lead-up to the final days before the Scottish independence referendum, which has thrust Cameron’s Conservative-Liberal Democrat coalition into an existential crisis.

With the polls too close to call, there is a very real possibility that the vote on Thursday will go in favour of independence or result in rejection, but by a very narrow margin. Either result could make Cameron’s position as prime minister untenable. By Friday morning, Cameron could have a third of the UK’s land mass no longer under his government’s control, pending full Scottish independence in 2016.

Under these conditions, the brutal murder of the two US citizens and now Haines is a very convenient diversion for a beleaguered UK government. These events are being seized on by the most rapacious sections of the ruling elite in Britain, who favour all-out war in Iraq and Syria and as a way of mending relations with the US after last September’s parliamentary vote against the bombing of Syria.

The war mongers see Britain’s involvement in a full-scale war in Iraq and Syria as akin to a “ Falkland’s moment” for the government. In 1982, with Britain mired in recession and unemployment at nearly four million, the three-year-old government of Margaret Thatcher was on the ropes. The widely despised Tory prime minister sent the armed forces to the Falklands Islands, 8,000 miles distant, to defend British imperialist interests in the South Atlantic in a war against Argentina. The Labour Party, which endorsed the war, was politically responsible for the revival in Thatcher’s political fortunes that followed the war, leading to her victory at the 1983 general election.

Last year, the Cameron government was signed up to participate in a long-planned US-led air war against Syria. However, amid widespread public opposition and divisions in ruling circles, it lost a parliamentary vote to back the US and secure agreement in principle for military intervention in Syria.

Numerous leading Tories, backed by sections of the military, have now come forward as the staunchest proponents of war. Liam Fox, a former defence secretary, told BBC radio, “It’s inevitable we will take military action against ISIS because our allies on the ground, the Kurds and the Iraqis, simply don’t have the level of the air power that they will require to degrade ISIS.”

London Mayor Boris Johnson, heavily promoted as Cameron’s eventual successor said, “We would be mad not to use our defence capability, where we can, to make the world a better place.”

Colonel Richard Kemp, former commander of British forces in Afghanistan, said “serious action” against ISIS was required, adding, “[T]he key issue here is that we cannot rule out the use of large-scale ground forces. I don’t mean the kind of thing that’s happening now. I mean large-scale intervention forces.”

Tory MP Bob Stewart, a former colonel, said, “Personally, I think we can’t say that we will never, ever put infantry on the ground, which is what we are talking about, because that actually, circumstances change … So until actually someone goes in on the ground, because you can’t win this from the air, someone has got to go and do the dirty work.”

Labour MP Ann Clwyd said she agreed with Stewart that it is “possible that we will eventually be sending ground troops.”

A number of Tories who voted against intervention in Syria last year have also declared their support for military action. MP Sarah Totnes said, “We should now as a matter of principle join the US in targeted air strikes.”

As with the previous wars in Afghanistan and Iraq, the plans to send British troops into the maelstrom in Iraq and Syria are being finalised in blatant defiance of international law.

Philippe Sands QC, a professor of international law at University College London, who repeatedly challenged the sham legal justifications for the Iraq war, said proposed action in Syria had no authorisation from the United Nations Security Council, there was no apparent evidence of the UK’s self-defence involved, and there was scarcely any basis for involvement on “humanitarian grounds.”

Sands added, “Calling this legal argument ‘wafer thin’ is generous on the basis of the evidence that I’ve seen, if indeed there is a justification that exists at all.”

A briefing note for MPs by the House of Commons library also warned on the legality of military action in Syria. “Action in Syria will be difficult to justify legally without a request for assistance from the [Syrian] Assad government, and it is unlikely that the West could be seen to be responding to such a request.”

It added, “The British government has said that any action in Syria will comply with international law, and the most likely way to achieve this would be to claim that military action is for humanitarian purposes, using the Responsibility to Protect doctrine. This remains controversial, however, without a United Nations Security Council resolution to authorise it.”