Jeremy Corbyn has been accused of “virulent anti-Americanism” after he blamed Britain and the United States for stoking conflict with Iran.

The Labour leader said Britain should not be fuelling a military escalation in the Gulf without “credible evidence” Iran was behind attacks on two oil tankers which dramatically heightened tensions in the region.

His comments were denounced as “pathetic” by Foreign Secretary Jeremy Hunt. who accused him of consistently failing to stand up for the interests of Britain and its allies.

Arriving for a Tory leadership hustings in London, he cited Mr Corbyn’s reluctance to denounce Russia over the Salisbury nerve agent attack on former spy Sergei Skripal and his daughter.

“For Jeremy Corbyn it’s all America’s fault. This is the same man by the way who refused to condemn Putin after the Salisbury Novichok attacks,” he said.

“I’m afraid this shows that Labour is in the grip of virulent anti-Americanism that will be incredibly dangerous for our country if they ever took control.”

Britain had broadly backed the US assessment that Iran was responsible for the explosions on Thursday on two tankers sailing through the Gulf of Oman – a claim Tehran strongly denies.

In a statement, the Foreign Office said “no other state or non-state actor could plausibly have been responsible” for the incident.

In response, Mr Corbyn tweeted: “Britain should act to ease tensions in the Gulf, not fuel a military escalation that began with US withdrawal from the Iran nuclear agreement.

Iran
An oil tanker on fire in the Gulf of Oman following an alleged Iranian attack (ISNA/AP/PA)

“Without credible evidence about the tanker attacks, the Government’s rhetoric will only increase the threat of war.”

Mr Corbyn’s comments were echoed by shadow foreign secretary Emily Thornberry, who said US hardliners like national security adviser John Bolton were trying to engineer regime change in Iran.

“These are extremely dangerous developments and we really have to pause and think about where we are going next,” she told the BBC Radio 4 Today programme.

“The idea that we are going to get enmeshed in another war is really something we need to think about very carefully. What we do not want is British forces being drawn into a conflict of that size.

“We have got to give up on this idea that if the United States decides to go into war – especially one engineered by the likes of John Bolton and the neo-cons – we have to stop and say there are times when we just don’t follow.

Iran
Donald Trump has blamed Tehran for the attacks, saying Iran ‘did do it’ (Jose Luis Magana/AP/PA)

“Harold Wilson did that with Vietnam and said ‘no’ to the Americans. We made a dreadful mistake when it came to Iraq and we must not make the same mistake again.”

The US has sought to back up its claims, releasing footage on Friday said to show an unexploded mine being removed from one of the tankers by Iranian special forces.

President Donald Trump told Fox News that Iran “did do it”.

“I guess one of the mines didn’t explode and it’s probably got essentially Iran written all over it,” he said.

Foreign Office sources denied a report by the official Iranian news agency, IRNA, that the British ambassador in Tehran Robert Macaire had be summoned to a meeting with a senior Iranian diplomat to complain at Britain’s  support for the US position.

Mr Hunt said Britain’s assessment “leads us to conclude that responsibility for the attacks almost certainly lies with Iran”.

“These latest attacks build on a pattern of destabilising Iranian behaviour and pose a serious danger to the region,” he said.