The environment secretary said she 'doesn't have final answers' after farmers demanded clarity on what the post-Brexit policies will mean for UK agriculture.

Defra minister Andrea Leadsom outlined her guiding principles for the creation of 'a more prosperous farming industry' while speaking at the National Farmers' Union (NFU) Conference in Birmingham.

'I do appreciate that your members are looking for clarity on specific issues – such as the future of direct payments, the prospects for seasonal agricultural workers, and access to the single market to name just a few,' she said.

'I want to be clear that as a major contributor to the UK economy – contributing close to £110 billion each year – there is no doubt that there will be support for our vital food and farming industry after we leave the EU.

'But I'm not going to stand here today and pre-empt the work the government is doing to get the best possible deal for the UK.

'Those negotiations will take time, and change is, of course, inevitable.

'But I want you to know that I will fight your corner at every opportunity – and fight for the huge contribution you make to our communities, to our environment, and to our economy.'

Ms Leadsom also said she had secured an agreement from the Treasury to offer a 75pc bridging payment to anyone with outstanding Basic Payment Scheme (BPS) claims at the end of March – with 4,000 people still awaiting their 2016 EU subsidy payment.

In his opening speech at the conference, NFU president Meurig Raymond called for more clarity on the union's three main priority areas for the Brexit negotiations – unrestricted access to the European market, continued access to a competent and reliable workforce, and a new agricultural policy which 'assists in the development of an increasingly productive, progressive and above all profitable farming sector'.

'We will need the government's support in all of these areas,' he said. 'Starting with keeping important trade routes open to ensure a smooth transition to new trading relationships with Europe post-Brexit with the best possible access to markets all over the world.

'Farming is reliant on being able to recruit both a permanent and seasonal workforce and we have a very serious challenge right now. The horticulture and poultry sectors – which are reliant on seasonal temporary workers – are already struggling to recruit up to 95,000 needed by 2021. We urge the cabinet to work with us to sort this out as a matter of urgency. British food production depends it.'