The profitability of the average UK farm could fall by as much as half after Brexit, indicates new research.
According to Agriculture & Horticulture Development Board (AHDB) report, the "worst-case scenario" would cut average farm profits from £38,000 a year to just £15,000.
The analysis considers the effects of cheaper imported food, reduced subsidies and more expensive labour.
According to a government spokesman the report is based on highly unlikely scenarios.
The UK would leave the European Union (EU) in March 2019.
Though formal negotiations with the EU started in June, it is still not clear how trade between the UK and the EU will change if the Brexit timetable is met.
The AHDB has, for the first time in its Horizon report, quantified the potential impact of Brexit on UK farming businesses.
The report considers a range of possible post-Brexit scenarios and models their effect on Farm Business Income (FBI) across agriculture and horticulture's levy-paying sectors.
However, even as the results are listed on a sector-by-sector basis, the top 25 per cent of farms, irrespective of sector remained profitable under every scenario.
According to AHDB, farmers now have the chance to learn from that high-performing group, which could serve as a benchmark for what is achievable in the way they run their own farm businesses.
According to Phil Bicknell, AHDB Market Intelligence director, the analysis underlines the fact that performance matters.
''As individual farms, we know that we can't determine policy but we can recognise that performance is key to preparing for the challenges ahead,'' Bicknell said, farminguk.com reported.
The analysis which launched at the AHDB's Grain Market Outlook Conference this week, projects the effect of different trading arrangements, farm support measures and labour availability.
These range from a no effect approach with levels of support remaining unchanged; a liberal approach to trade with tariff-free access to the UK and reduced support; to hard Brexit, reverting to WTO regulations and with dramatically reduced support payments.