An independent regulator must be established to ensure farmers and landowners meet minimum standards to protect water, soil, wildlife and animal welfare after Brexit, campaigners have urged.

The Nature Friendly Farming Network (NFFN) says the nation's long-term food security could be at risk unless there are 'ambitious' minimum standards for the industry in the government's Agriculture Bill, which sets out domestic policy for the sector as the UK leaves the EU.

An independent regulator should support farmers to move towards nature-friendly farming practices with high environmental, production and animal health and welfare standards, says the NFFN.

The organisation, which was launched a year ago, warns soils have become depleted and water courses degraded, while populations of birds, butterflies and other species such as hedgehogs have seen numbers fall significantly.

Ministers have set out plans to pay farmers for providing 'public goods' such as habitat for wildlife, planting trees to curb flooding and managing soil well, after the UK leaves the EU-wide Common Agricultural Policy (CAP) subsidy scheme.

But the NFFN wants farmers who choose to focus exclusively on farm food production, using intensive methods, to be required to keep their land in 'good heart'.

Targets in areas such as air quality, water quality and soil health will act as an incentive to those who are currently failing to deliver public goods alongside food production, the NFFN argues.

The call comes as environment secretary Michael Gove is set to address the Oxford Farming Conference on the future of agriculture after Brexit.

Cambridgeshire farmer Martin Lines, who chairs the NFFN, said: 'It is the secretary of state's duty to establish an independent regulator before it's too late.

'We can only guarantee long-term food security by protecting and managing the natural assets which enable food production.

'If the Government does not amend the bill to include minimum standards – and put a stop to the environmental degradation caused by intensive farming – British farmers will be in danger of losing their livelihoods.'

In his speech to the Oxford Farming Conference today, Mr Gove will pledge to make the case for long-term investment in British farming and is also expected to reiterate his support for the Prime Minister's Brexit deal, which he says will avoid the disruption of crashing out of the CAP with no deal.

Mr Gove said: 'While I cannot pre-empt the outcome of the government's spending review later this year, I can continue to demonstrate the case for, and put in place the policies that underpin, long-term investment in British agriculture and the rural economy.

'It is also one of the reasons why I hope my colleagues in Parliament support the prime minister's deal.

'It isn't perfect, but let's not make the perfect the enemy of the good.

'It not only gives us a 21-month transition period in which current access is completely unaffected, it also allows us to maintain continuous tariff-free and quota-free access to EU markets for our exporters after that.'