MPS have raised concerns over the Environment Department’s “blind optimism” on its plans for post-Brexit farming and land payments.

Farmers have been “left in the dark” by a lack of detail on the environmental land management (ELM) scheme that will replace the EU Common Agricultural Policy (CAP) subsidies in England over the coming years, papers say.

The new regime includes a programme to support local nature on farms and “landscape recovery” funding for large-scale projects, which could include rewilding, as well as payments for farmers to farm more sustainably.

The Public Accounts Committee (PAC) said the Department for Environment, Food & Rural Affairs (Defra) has not set out how increases to productivity or environmental benefits will be delivered by the scheme – or how it will offset the huge impact of cutting current direct subsidies by more than half by 2024/25.

Its report said Defra “concedes its confidence in the scheme looks like blind optimism without the details of what it has planned”.

The MPs said the lack of information from Defra early enough to allow farmers to plan was causing anxiety in the sector – exacerbated by a historic lack of trust caused by past failures to manage farm payment schemes.

It raised concerns Defra had not explained how changes in land use would not lead to more food being imported, with the environmental impacts of production being “exported” to countries with lower standards.

It said Defra had not established robust baselines or clear objectives to allow it to measure the success of the scheme and whether the £2.4 billion a year on agricultural schemes was providing value for money.

Defra’s engagement with the farming sector is improving “but there is still a long way to go”, the PAC said.

The MPs urged the Government to explain how it thinks its farming programmes will affect food production and farm productivity, review its communications strategy, and set out how it will incentivise young farmers to come in to and stay in the sector.

They also warned Defra it needs to identify what further support is needed to help farmers during the transition, including where farmers will face significant business challenges in the short term.

The removal of direct payments, which focus on the amount of land owned rather than environmental schemes, would have reduced the average net profit of farms in England by 53% over the last three years to £22,800.

Without direct payments, more than a third of farms would have made a loss and so be unsustainable without changes such as rent reductions, increased productivity, or income from new schemes, the report said.

PAC deputy chairman Sir Geoffrey Clifton-Brown said: “We have known we were replacing the CAP since 2016 and still we see no clear plans, objectives or communications with those at the sharp end – farmers – in this multi-billion pound, radical overhaul of the way land is used and, more crucially, food is produced in this country.

“Farmers, especially the next generation of farmers who we will depend on to achieve our combined food production and environmental goals, have been left in the dark and it is simply wrong that Defra’s own failures of business planning should knock on to undermine the certainty crucial to a critical national sector.”

Sir Geoffrey added: “The recent energy price crisis should be a salutary warning of the potential risks to the availability and affordability of food if the UK becomes even more reliant on food imports.”

Environment Secretary George Eustice said: “We disagree with many of the points made by the Committee which fail to take account of recent developments.

“Farm incomes have improved significantly since the UK voted to leave the EU in 2016 and there will never be a better time to improve the way we reward farmers.

“In December, I set out comprehensive details of the Sustainable Farming Incentive including full payment rates and we published an in-depth analysis of UK food security and agricultural output.

“In the past week we’ve shared further details of the Local Nature Recovery and Landscape Recovery schemes and announced a major increase in payment rates for those farmers involved in existing agri-environment schemes.”