However, on-the-ground experience from these grand farm units is that the annual net profit is no longer coming from the traditional farming enterprises of dairy, beef, sheep or arable but instead from alternative uses such as house rentals, commercial unit lettings of former grain and potato stores and a host of other non-traditional farming activities.
Of course, the EU Basic Payment Scheme and the myriad of environmental schemes are also a huge source of annual income. Many of these estates have lost their heart and soul created by the traditional mixed farming activity of crops and livestock, all centred around the grand period mansion and wonderful cut-stone outbuildings.
Instead, they have become a cold group of companies and businesses ranked by return on capital and various other financial metrics.
Post-Brexit, one has to question if the poor return on capital from the land farmed in these estates will cause the number crunchers to recommend selling the land to invest in more lucrative ventures elsewhere in the world? This could be the beginning of the end for large English estates.
The Brexit exit negotiations are scheduled to conclude by March 2019. There are four overlapping sets of negotiations that affect agriculture in this process:
Regulation
There are many EU regulations which must be incorporated into British law or scrapped altogether. The big question is how will this impact the British people? Is it a big opportunity for a new start?
These are all fascinating questions but they will take many years to answer.
People
The free movement of people is one of the four freedoms of the European Union. There are 130,000 non-British people employed in agriculture in the UK, but there are many more in other industries. This is a huge concern from many businesses in the UK. Who is going to do the work the locals will not do?
Trade
The UK is a net importer of food, being only 60pc self-sufficient. Trade and importation of food has always been part of the British economy.
The agricultural industry imports a lot of raw materials from Europe, which is a worry for farmers, but the big worry is tariff wars. The farmers are worried about zero-tariff imports of food, as a trade-off for British exports. This is a genuine worry with the lack of political influence in the industry.
Policy
The EU Common Agricultural Policy and its generous payments to large UK farms is the great big paradox of Brexit. Many farmers openly state their opinion that it is better for them that EU subsides go so that they are free to farm.
Yet they claim that the government in Westminster will replace EU subsidies with a British equivalent, heavily linked to environmental measures. The big worry is that if Britain spins into an economic recession, will Westminster honour its promise or scrap agricultural subsidies altogether?
The British agricultural industry is calculating and speculating on the likely impact of Brexit, but as a show of hands after a discussion at the Nuffield Triennial demonstrated, they are split 50:50 as to whether it will be good or bad for their industry.
Indecision is the mother of all evils.
Mike Brady is an agricultural consultant and land agent based in Cork. email: mike@bradygroup.ie