Landowners including the Queen should lose up to £1 million a year under plans to slash farming subsidies for wealthier farmers after Britain leaves the European Union, campaigners have said.

One Labour MP said it was "indefensible" that wealthy land-owning families are given so much money in subsidies, and another campaigner said it was a "no-brainer" to change the system after the UK leaves the EU.

Farm minister George Eustice has also in the past said the distribution of payments was 'unfair'.

Lands operating on the Queen's Sandringham Estate in Norfolk receives £700,000 a year in government funding, while farms near Windsor Castle receive £300,000.

Mr Eustice told Politico: "I don’t think many people could defend the notion of an area-based subsidy system staying in place for perpetuity.

"It’s a little bit upside down because it means the largest payments go to the largest landowners who arguably need it the least," he said.

Landowners featured in the Sunday Times Rich List last year received more than £10 million between them.

Defra secretary Michael Gove recently said future farm subsidies must be assessed on environmental and public benefits the land brings rather than simply how much land is owned.

Under the current CAP, 80% of funds go to 20% of farms, as funding is determined by the amount of acreage a farm has.

Mr Eustice and the Conservatives are trying to prioritise smaller farms as Britain begins negotiations to leave the EU.

Chris Byrant, Labour MP for Rhondda, told The New York Times: “It’s completely indefensible, the only way we have been able to defend it in the past is that it is a European Union system,” he said.

“The British government has for years argued that we spend too much on agriculture, and the logical consequence of that would be not to have such high subsidies."

Oxford economist Dieter Helm told the paper it was a "no-brainer" to change the system: “The one shining opportunity is that we don’t have to be involved in this.”

“There is a natural evolution away from paying people who have several thousand acres and toward the smaller farms, which tend to be in the uplands. It’s a no-brainer.”