The Labour party under Jeremy Corbyn has rightfully much to boast about when it comes to green policies. The party says it will ban fracking, spend £2bn a year to insulate homes and build a net zero-emission economy by 2050. Meeting such targets will need politicians to fend off vested interests and their special pleading. Big reforms are easily scuppered by entrenched industries. So it is strange that when plans to change the face of rural Britain in a positive way come before MPs, Labour’s environment team, headed by Sue Hayman, has been accused of trying to wreck them with arguments that put the party on the side of the status quo.

The allegation came as Michael Gove, the environment secretary, is taking the first agriculture bill for seven decades through parliament. It aims to replace the harmful and unfair EU common agricultural policy, which is based on the majority of the direct EU support payments going to farmers for acres owned. “The more you have, the more you get” mentality created a perverse incentive to clear wildlife habitats, even in places unsuitable for farming, to attract cash. Rich landowners were rewarded for their holdings’ size rather than for restoring peat bogs and hedgerows. Mr Gove rightly wants to move to a system that links a much bigger slice of payments directly to farmers’ delivery of “public goods”, notably “environmental protection and enhancement”. As a leaver, he sells Brexit as an opportunity and takes up the cause of campaigners who argue the current model of farming has been behind the collapsing bird and insect numbers in the countryside and is why our rivers are so mucky. It is good Mr Gove recognises the importance of ecosystems for farming. The bill is imperfect and Mr Gove himself is often heavy on style and light on substance, but the direction of travel ought to be welcomed.

Having said that, agriculture would wither without subsidies. British farmers receive payments worth £3bn a year. Post-Brexit, the plan is for farmers to get the equivalent of the CAP subsidies until 2022. Payments will then be phased out and replaced by the new system. The importance of the government cash should not be underestimated: it makes up almost two-thirds of farm income in England and three-quarters in Scotland. Many farmers voted for Brexit because they were fed up of CAP’s bureaucracy. They are now nervous of facing a unpalatable choice: seek government cash for creating public goods or try to increase efficiency to survive on lower subsidies.

There are risks that farmers will go bust before they can go green. Britain might need to suck in cheaper imports, produced wherever the cost of land and labour compensates for longer logistics chains. There is a recognisable political dilemma here: how to achieve radical change without creating an immovable opposition. Emmanuel Macron demonstrates the danger of clumsily loading green costs upfront. Labour is aware that half a million jobs are at stake. The danger is the party trades its principles for opportunistic gain. It ought to focus on holding the government’s feet to the fire over retaining the level of agricultural support and a proper watchdog. It might push co-operative farming, which lowers costs by getting farmers to work more closely together. It could tax land more fairly. We need to make food production sustainable in an era of climate crisis. The bill’s fate is now tied up with that of Brexit. It will not return to the Commons until after the meaningful vote. Labour has time to show it can produce its own policy that reflects the party’s green commitments as well as concerns over food security.

• This article was amended on 28 November 2018. An earlier version said the importance of the government cash cannot be underestimated, when should not be underestimated was meant.