Two former foreign secretaries have joined debate over the assassination of General Qassem Suleimani, with Jeremy Hunt saying it exposes cracks in the Western alliance and Jack Straw calling it a gamble by Donald Trump and linking it to his re-election bid.

Mr Hunt, the Tory foreign minister for a year under Theresa May, says the killing of the Iranian general without consultation from the United States to countries including Britain reflected a growing disregard toward Europe from Washington.

This stemmed mostly from American disenchantment with defence spending by European countries, which invest 2% of their GDP or less on defence whereas the US spends 4%.

Iran Soleimani
A crowd said by Tehran police to be in the millions turns out for the funeral of General Suleimani on Monday (Office of the Iranian Supreme Leader/AP)

“American taxpayers still fund around one third of the cost of defending Europe, a massive subsidy to already-prosperous Europeans,” Mr Hunt wrote in The Daily Telegraph.

“If the best the Europeans can manage is half the proportion spent by the US it hardly reassures the hawks in Washington.

“In the end, money matters. If we’re not prepared to cough up we should not be surprised if we are not consulted ahead of big decisions such as the taking out of General Suleimani. Nor should we be surprised if the Western alliance slowly starts to fracture as resentment builds up at European free-riding. To allow that would be a historic mistake.”

Mr Hunt said many in Washington would happily abandon institutions such as NATO for an alternative scenario in which powers like the US, Russia and China “carve up the world into spheres of influence”. If Britain did not want that, it had to behave “like a real ally” to the US and pull its weight in global affairs, including making “proper” contributions to world peace and security and persuading EU countries to do the same.

Mr Straw, Labour’s foreign secretary from 2001-06, said Mr Trump had done what other major stakeholders had decided was not worth doing in ordering the killing of General Soleimani, saying predecessors George W Bush and Barack Obama, along with Israel, had “judged the costs of doing so far outweighed any benefits”.

“They were right,” Mr Straw wrote in The Times. “Aside from any deaths of American, Israeli, or other westerners in reprisal for Soleimani’s killing, there will be wider consequences adverse to US and Israeli interests, and beneficial to Iran.”

Rather than a pre-emptive strike against the killing of Americans by Iranian-backed forces, Mr Straw linked the strike to Mr Trump’s re-election bid, and called it a gamble which would “play into the hands of the hardliners in Iran”.

“Whether it all helps President Trump’s re-election remains to be seen,” he wrote. “But if so, what a price to pay.”

Meanwhile, retired diplomat Sir Paul Lever, former chairman of the UK’s Joint Intelligence Committee, concurred with Mr Hunt that Britain – like France and Germany – should not expect to be involved in America’s manoeuvrings in regard to Iran.

“We have interests to protect in the region (by re-grouping our forces in Iraq to more defendable locations and by re-instituting convoys in the Strait of Hormuz),” Sir Paul wrote in a letter to The Times.

“But we should not pretend that we are a significant political player. We are not consulted by the United States and we have no influence over Iran. We can only watch and wait. This is the reality of being a middle-sized power.”