The government has said it is stepping up plans to offset potential food and fuel shortages caused by the Iran war.

Sir Keir Starmer will chair another meeting of a Cabinet committee on Tuesday set up to deal with any shortfalls and a group of ministers is meeting twice a week to monitor stock levels and any disruptions to the supply chain.

The closure of the Strait of Hormuz, a key shipping channel through which 20% of the world's oil and liquid natural gas usually passes, has sent oil prices soaring since the conflict began.

Earlier this month, government officials drew up a worst case scenario of food shortages, including chicken and pork, by the summer if the war continues.

The government has also been seeking to calm the public, urging drivers to keep filling up with petrol and using cars as usual and not to change their travel plans amid fears over potential jet fuel shortages.

Twice weekly meetings of the contingency planning group of ministers are being led by Darren Jones, Chief Secretary to the Prime Minister, who said: "This is not our war. The government made the right call to stay out of the conflict and only take defensive action to protect Britain's interests.

"We're acting now to prepare for, and mitigate where possible, the impact on our economy and domestic security as a result of the conflict."

Last week, the International Monetary Fund (IMF) predicted the energy shock from the Iran war would hit the UK the hardest of the world's advanced economies, and cut its estimate for UK growth this year to 0.8% from its previous prediction of 1.3%.

Jones said that while the government will do everything in its power to find a permanent solution to the crisis and offset its impact, "what happens abroad will still affect us here at home".

A government source previously told the BBC it was planning for a scenario which would involve breakdowns in the supply of carbon dioxide (CO2), which is used in the slaughter of some animals and in food preservation, if the strait remains closed.

The government has provided funding to reactivate the Ensus bioethanol plant, which makes CO2 as a by-product, in order to shore up supplies of the gas.

A spokesperson for the plant told the BBC they were "confident we can continue to produce CO2 for the country's needs for the foreseeable future".

Jones said: "People should carry on filling up and using their cars as normal, shipments of jet fuel are continuing to arrive in the UK and the UK's critical supply of CO2 has been shored up."

The majority of the UK's CO2 is imported from Europe but it is often produced as a by-product when companies make fertiliser, which needs natural gas.

Supermarkets have said they are working with the government to help plan for a worst-case scenario.

And, last month, the National Farmers' Union said cucumber and tomato prices could rise over the next six weeks, with the cost of other crops and milk increasing in the next three to six months.

UK airlines have insisted they are "not currently seeing a shortage of jet fuel" as they buy it in advance and airports maintain stocks.

The Liberal Democrats have urged the government to include a bill in the next King's Speech which puts food security at the top of the government's agenda.

The party's Cabinet Office spokeswoman Lisa Smart said "the government also needs to wake up and provide more support to people who simply cannot afford the sky-high cost of getting around".

She added that the Lib Dems have proposed a 10p cut on fuel duty as well as reducing public transport costs.

Iran's top negotiator said earlier this week that reopening the Strait of Hormuz is "impossible" if the US continue their naval blockade of Iranian ports.

US President Donald Trump hopes to put pressure on Iran by targeting two economic drivers - the tolls the country was demanding ships pay to pass through the Strait of Hormuz, and Iran's oil revenue.

Iran has responded by calling the blockade "piracy". Negotiators from the country were in Islamabad, Pakistan, on Saturday for talks on ending the conflict.