Household food staples such as bread and pasta are set to remain more expensive in the long term, a report has warned.

Price rises caused by 'major shocks' - such as the crisis in the Middle East and the El Nino weather pattern - tend to fall back down slowly and not always entirely, the analysis claims.

The Energy and Climate Intelligence Unit (ECIU) said these events leave households facing a higher grocery bill long after the original crisis has eased.

On average, shelf prices fall just one per cent of the original rise after six months, five per cent after a year and seven per cent after two years, the think-tank found.

In wage-adjusted terms, only a third (35 per cent) of the affordability shock had unwound after two years.

The report, based on more than 30 years of UK data, suggests that this 'rocket and feathers' effect – where food prices 'shoot up like rockets but drift down like feathers' – helps explain why food prices remain far above pre-pandemic levels even after some of the shocks that drove them have eased.

ECIU food and farming analyst Chris Jaccarini said: 'Shoppers feeling that prices are on a never-ending escalator upwards is borne out by the data.

'War and extreme weather are increasingly pushing up the cost of the weekly shop with the latest conflict in the Middle East driving up the price of oil, gas and fertiliser used to grow, ship and process food.

'In England, we've had three of the worst harvests on record in the past five years and next year is shaping up to be the hottest globally.

'The only way to stop the growing risk of floods and droughts is to reach net zero and bring the climate back into balance.

'That means cutting our reliance on oil and gas, which would also help shield food prices from the volatile global markets that have helped drive the cost-of-living crisis.

'As the data shows, once prices are up, they're up – prevention is the only cure.'

Henry Dimbleby, former lead of the government's National Food Strategy, said: 'Food inflation has been brutal – and it will keep biting unless we tackle the underlying causes.

'That's because our food system is tightly tied to energy, fertiliser and transport costs – and we've built too little resilience into supply chains and production.

'As climate change and energy volatility worsen, shocks are likely to become more frequent and more severe.

'Unless we cut our reliance on fossil fuels, diversify supply chains and build real resilience into food production, higher food prices will become a lasting feature of daily life, with the heaviest burden falling on those least able to bear it.'

The ECIU said warmer El Nino temperatures tended to particularly affect cocoa, food oils, rice and sugar, with wider risks for other products linked to the tropics such as bananas, tea, coffee, chocolate and soy-fed meat.

Households have already seen food prices rise more than 40 per cent since mid-2021, the report said.