We all look to the past with rose tinted spectacles – but even without those, there was an era when Conservative governments really cared about farming.

Think back to ministers like Peter Walker, Michael Jopling, John Gummer, John MacGregor – the list is long and honourable and the department then was responsible for 'agriculture, fisheries and food. Today, agriculture has disappeared from the title of Defra – replaced by rural affairs, which sounds like a term for illicit liaisons in the countryside.

That lack of interest is something farmers have learned to live with, but things hit a new low when a government adviser made the serious suggestions, apparently, that we could do without having a farming and food industry. His idea was that we could be like Singapore, importing everything and growing nothing while high tech companies and financial services drove the economy.

This is clearly a risible suggestion, but with Boris Johnson's adviser, Dominic Cummings – the Prime Minister in all but name – it is not surprising another maverick adviser should grab headlines.

Pull the focus back from this suggestion and bizarre as it may be, it contains seeds of logic. The government in London, although thankfully not yet in Edinburgh, is changing its relationship with farmers.

When land-based payments are phased out in seven years, support will be purely for public goods, in the shape of the environment and animal welfare. It is a short move from that to argue that the UK does not need a farming industry to have a food industry.

That argument, however, forgets issues like quality, provenance and in an increasingly risky world, food security. But we are dealing with knee-jerk politics rather than long-term thinkers.

Importing food for processing would ease the government's task in securing trade deals. Some will argue that such an approach would deliver the best economic outcome, with only farmers losing out – just as coal miners and steel workers did in the past.

This is a case of 'don't shoot the messenger'. I fundamentally disagree with this approach and still believe Jonathan Swift, in the 1700s, was right when he said those 'who grow two blades of grass when one grew before' are more worthy of the praise of mankind than politicians.

However, the reality of a government with a massive majority seeing votes from being seen to be green cannot be ignored. If farmers allow this thinking to gain any traction, they will be the losers.

This is not a problem unique to the UK. The key driver for the last European Commission was economic growth and it did well securing a number of key trade deals – the biggest being with Japan. That policy has seen agriculture and food exports reach record levels, with a growing gap between exports and imports.

The new commission's vision is rooted in a green deal. This is about achieving a zero carbon economy at some point while delivering a 50% reduction in greenhouse gas emissions by 2030, compared to 1990. This is the goal driving all policy and agriculture is part of it.

The key question now is whether the UK will continue seeking to out-green an ever greener EU 27, since carbon reductions are a central issue for all governments.

With every worthy objective there are problems. The agriculture part of the EU's green deal policy is a new 'Farm to Fork' strategy. This has many worthy objectives, ranging from reduced use of antimicrobials through sustainable farming methods to reduced food waste by retailers and consumers.

This is real motherhood and apple pie politics that anyone would find difficult to criticise. However, the problem with green support policies is that they become a bandwagon for others to mount.

This is already happening with the F to F strategy. Green groups are saying it must be rooted in policies to curb meat, dairy and egg production because in a green context in the EU these are 'inherently unsustainable'.

Calls like this are hard to ignore and that is the problem with big catch all environmental policies that look good on paper, but lack joined up thinking. When people leap onto the bandwagon they become difficult to ignore and the good intentions of a policy are eroded.

This is happening in Brussels; it is also happening in London with the government's policies for English agriculture. We need to make sure the 'contagion' does not spread to Edinburgh.