Keir Starmer hit out at Donald Trump's blockade plan today insisting the Strait of Hormuz must be 'open, not shut'.

The PM confirmed that the UK will not be playing any part in the US President's latest move as he voiced 'concern' about the impact on the economy.

Brent Crude is trading above $100 a barrel again after marathon negotiations with Iran failed to get an agreement.

Mr Trump has vowed to blockade 'any and all ships' attempting to use the vital Strait of Hormuz - through which around a fifth of the world's oil and gas passes.

However, it is unclear what the move, which took effect at 3pm, means in practice, with Iran already stopping most tankers getting through. 

Appearing on BBC Radio 5 Live this morning, Sir Keir said the UK was 'not supporting the blockade' - with a joint UK-French summit on a peacekeeping mission due to take place this week.

'What we've been doing is bringing countries together to keep the Straits open and not shut,' the premier said. 

'All the time the Strait is shut or not that means oil and gas is not getting to market, the price is going up. 

'It is vital that we get the strait open and fully open.' 

Brits are bracing for more pain with pump prices already rocketing, energy bills set to follow, and hopes of interest rate cuts on hold. 

The Resolution Foundation think-tank has warned that typical middle-earner households will be £480 worse off this year than they would have been without the economic shockwave.

But Sir Keir refused this morning to commit to any action on fuel duty - which has been cut by many other countries, but is due to rise in the UK in September.   

As the world hold its breath again today:

• The RAC said petrol and diesel rises had been slowing before the latest spike in oil prices;   
• The president lambasted Nato - a defensive alliance - for refusing to get involved in the US-Israeli war against Iran;
• He insisted Iran will come back to the negotiating table because otherwise he would send the country 'back to the Stone Ages'. 
• Mr Trump renewed his war of words with Pope Leo XIV, who previously criticised the president's rhetoric regarding the conflict;
• Rachel Reeves is due in Washington for talks with IMF counterparts as the economic consequences start to be felt. 

'The blockade will be enforced impartially against vessels of all nations entering or departing Iranian ports and coastal areas, including all Iranian ports on the Arabian Gulf and Gulf of Oman,' it said.

'Centcom forces will not impede freedom of navigation for vessels transiting the Strait of Hormuz to and from non-Iranian ports.'

Sir Keir stressed 'the need to work with a wide coalition of partners to protect freedom of navigation' in the Strait as he spoke to French president Emmanuel Macron last night.

Mr Trump wrote on social media: 'Any Iranian who fires at us, or at peaceful vessels, will be BLOWN TO HELL!' He said the US would 'finish up the little that is left of Iran', adding: 'THIS IS WORLD EXTORTION.'

'We're putting on a complete blockade,' he told Fox News. 'We're not going to let Iran make money by selling oil to people that they like, and not people that they don't like. It's going to be all or none, and that's the way it is.

'We're going to clean out the Strait and [ships] will be able to use it in not too long a distance.'

Mr Trump said that 'the UK and a couple of other countries are sending mine sweepers' to the strait, and 'it won't take long to clean it out'.

However, although Britain does have mine hunting systems in the region, they are thought to be drones and would only be deployed once the situation stabilises. 

Sir Keir said: 'The ongoing closure of the Strait of Hormuz is deeply damaging. Getting global shipping moving is vital to ease cost of living pressures.

'The UK has convened more than 40 nations who share our aim to restore freedom of navigation.

'This week the UK and France will co-host a summit to advance work on a coordinated, independent, multinational plan to safeguard shipping when the conflict ends.'

Emmanuel Macron said: 'This strictly defensive mission, separate from the warring parties to the conflict, is intended to be deployed as soon as circumstances permit.' 

There are reports that Mr Trump is weighing up resuming limited military strikes in Iran in addition to the blockade in order to find a breakthrough on the peace talks.

It came as Tehran's foreign minister claimed it was 'inches away' from agreeing a deal with the US.

Oil and gas prices have soared and stock markets have fallen since the Strait was closed by Iran at the start of its conflict with the US in February.

Airlines have warned of higher ticket prices as jet fuel costs have doubled, and supermarkets are likely to introduce price hikes due to higher importing and packaging costs.

Yesterday, Mr Trump said Iranian explosives would be cleared from the Strait by minesweepers, including some from the UK.

'We have highly sophisticated underwater minesweepers, which are the latest and the greatest, but we're also bringing in more traditional minesweepers,' he said.

'I understand the UK and a couple of other countries are sending minesweepers.'

The blockade plan comes after peace talks with Iran, led by US Vice President JD Vance in Islamabad, Pakistan, broke down on Saturday.

While the discussions took place, Mr Trump attended an Ultimate Fighting Championship (UFC) match in Miami.

A UK Government spokesman said: 'We continue to support freedom of navigation and the opening of the Strait of Hormuz, which is urgently needed to support the global economy and the cost of living back home.

'As an international shipping route, the Strait of Hormuz must not be subject to tolling.

'We are urgently working with France and other partners to put together a wide coalition to protect freedom of navigation.'

The Resolution Foundation study found typical working-age households were previously on course for a 0.9 per cent, or £300 boost, to their incomes this year.

But they will now instead find themselves 0.6 per cent, or £180, worse off.

It means overall they are losing out to the tune of £480 from the inflation shock.

The analysis shows that the removal of the two-child limit on benefits will deliver a major boost to those with three or more children who are in the bottom half of UK earners.

They will see their living standards rise by an average 7.7 per cent, even after the shock of rising prices caused by the conflict.

This compares with 0 per cent for poorer families with fewer than three children.