A no-deal Brexit could be 'catastrophic' for farmers – potentially preventing exports of animals and animal products to the EU for six months, industry leaders have warned.

The National Farmers' Union (NFU) said the latest set of technical notices published by the government outlined a potential 'cliff-edge' scenario for livestock farmers where exports to the EU are blocked, but imports continue to flood in.

If no trade deal is reached, the papers suggest the UK would need to be approved by the EU as an exporter for animal products – a process which could take a minimum of six months.

The government says, in this scenario, export health certificates and border inspections would be required from the end of March 2019 and the UK would need to become a listed 'third country' before any exports could take place, but Defra acknowledges it 'cannot be certain of the EU response or its timing'.

The NFU says this underlines the critical importance of a deal that allows free and frictionless trade with the EU – a market which buys agri-food exports worth an estimated £13bn from the UK, including £3.15bn of animal and animal products.

NFU president Minette Batters said: 'These technical notices confirm in black and white what we already knew: a no deal scenario would be catastrophic for British agriculture. A scenario where farmers face an immediate trade embargo for many of their products would have devastating effects, and would severely threaten livelihoods and businesses.

'While these notices are an essential part of government planning, it is crucial that the government does as much as possible to avoid disruption for farm businesses in all outcomes. We urge everyone in the negotiations to work to achieve a deal that delivers free and frictionless trade between the UK and the EU.'

One of East Anglia's key farming sectors is pigs, with an estimated 20pc of the national herd kept in Norfolk and Suffolk.

National Pig Association chief executive Zoe Davies agreed that a no-deal Brexit could have catastrophic consequences for a sector increasingly underpinned by export trade.

Dr Davies said: 'A 'no deal' could be the worst of all worlds for the UK pig industry. If exports are blocked but we continue importing pigmeat from the EU in large quantities, as the government appears willing to do, it would blow a huge hole through the economics of the UK pig sector.

'Because of carcass balance issues, the UK would be swamped with pigmeat that had little value on the domestic market, dragging down the pig price and making it very difficult for many pig businesses to continue operating.

'As we have repeatedly stated, EU trade is critical to ensure the UK pig sector can function properly. It is therefore essential that the government does everything in its power to secure frictionless trade after we leave the EU.

'But in the event of a no deal, we expect a much more forward thinking and cohesive plan from the government than the flimsy and uncertain arrangements contained in this document. If the situation persists, it could result in the collapse of the supply chain with producers and processors going out of business.'

The NPA says more than 110,000 tonnes of pig products were exported to the EU in the first seven months of this year, equating to nearly 60pc of all UK pigmeat exports.

Defra said it was 'taking steps to minimise disruption in the event of no deal'.