Anti monarchy campaigners are calling on the King and the Prince of Wales’ duchies to be abolished and replaced with a new national estate to benefit the “common good”.

Charles receives an annual private income from the Duchy of Lancaster landed estate of £27 million, while William is entitled to more than £23 million a year from the Duchy of Cornwall.

Republic, which backs an elected head of state, is urging the Government to abolish the ancient Duchy portfolios and pass all revenue and assets to a new national estate to support local communities.

Republic proposes Charles, while he is head of state, “should receive a salary”.

Protesters from Republic in the crowds during the King’s visit to Middlesbrough (James Glossop/The Times/PA)

The campaign group suggests this could be 110% of the Prime Minister’s salary – a drop from £27 million a year to about £190,000.

But it adds: “William has no official role and needs no salary from the state.”

The group’s report, Ditch the Duchies, states: “The national estate could invest that wealth into local communities, while offering leaseholders the right to buy freehold and ending needless charges to charities and public services.

“The national estate’s purpose will be the common good, not lining the pockets of two royals.”

The King during a visit to Tower Brewery in Burton upon Trent on Monday (Jaimi Joy/PA)

It said: “How can we defend an annual income of more than £27.4 million for our head of state, more than 159 times that of the Prime Minister?

“The answer is that these incomes cannot be justified. And it is time government and parliament scrapped this indefensible arrangement. The solution is simple: abolish the duchies.”

An investigation into the duchies in November, by Channel 4’s Dispatches and The Sunday Times, found the estates have struck rental agreements worth millions of pounds with the armed forces, the NHS and state schools.

The Duchy of Lancaster agreed a deal to store ambulances in a warehouse on its land at a cost of more than £11 million to the NHS over 15 years, while the Ministry of Justice pays the Duchy of Cornwall £1.5 million a year to use Dartmoor Prison.

The Prince of Wales is entitled to the net surplus of the Duchy of Cornwall which comes to £23 million a year (Kirsty Wigglesworth/PA)

Republic argues the duchies are public property and state assets, and adds: “At a time when services are being cut, when more people are turning to charity and charities are struggling to keep their doors open, it is time Parliament gifted that land and its revenues to local communities, not the royals.”

The Duchy of Lancaster is land, property and assets which is held in trust for the sovereign, and provides the King with an income separate from the taxpayer-funded Sovereign Grant.

It has been the personal estate of the reigning monarch since 1399 and spans more than 18,000 hectares of land in England and Wales and comprises commercial, agricultural and residential properties mostly in Lancashire, Yorkshire, Cheshire, Staffordshire and Lincolnshire.

It gives the monarch a source of income for funding – in the form of the net surplus – his private activities and some official expenditure, but the breakdown of how the King spends the private money – which is independent of the Government – is not released.

HMP Dartmoor in Devon (Ben Birchall/PA)

William is entitled to the surplus profits of the Duchy of Cornwall estate and the money is used to fund the official, charitable and private lives of the Prince and Princess of Wales and their children: Prince George, Princess Charlotte and Prince Louis, but not their official travel.

The duchy was created in 1337 by Edward III to support his son and heir, Prince Edward, known as the Black Prince, and all his subsequent heirs.

It extends across 23 counties in England and Wales and includes the Oval cricket ground and 67,000 acres of Dartmoor.

The Duchies of Lancaster and Cornwall declined to comment.