Revealed: Queen vetted 67 laws before Scottish parliament could pass them

The Scottish government has given the Queen advanced access to at least 67 parliamentary bills deemed to affect her public powers, private property or personal interests under an arcane custom inherited from Westminster.

The Queen’s consent procedure, which critics have called anti-democratic, has been used repeatedly by the monarch in recent decades to secretly lobby for changes to proposed UK legislation before it is passed by parliament.

The extent of the practice in Scotland, where it is known as crown consent, has until now been unknown to the public.

Related: Queen secretly lobbied Scottish ministers for climate law exemption

Research by the Guardian has identified 67 instances in which Scottish bills have been vetted by the Queen in the last two decades. They include legislation dealing with planning laws, property taxation, protections from tenants and a 2018 bill that prevents forestry inspectors from entering crown land, including Balmoral, without the Queen’s permission.

Willie Rennie, who recently stood down as leader of the Scottish Liberal Democrats, called for more transparency, adding: “The SNP government must come forward and share the full extent to which this process has influenced the laws we live under.”

Royal courtiers and the Scottish government declined to say how many of these laws were amended as a result of the monarch’s lobbying.

However, the Guardian revealed how the Queen’s lawyers recently successfully persuaded a Scottish minister to give her an exemption from a law that was designed to cut carbon emissions through the construction of heat pipelines.

Evidence of the lobbying effort, which took place five months ago, is contained in a slew of documents obtained by Lily Humphreys, a Scottish Lib Dem researcher, using freedom of information laws.

The correspondence shows how the monarch is allowed to vet draft laws that potentially affect her sprawling private estate around Balmoral Castle in the Highlands.

The estate has received hundreds of thousands of pounds in farming and forestry subsidies. These have included EU funds for the Highland cattle the Queen breeds at Balmoral, environmental improvements, rural development and, most of all, forestry. In 2018, Balmoral was given nearly £107,000 in EU subsidies, including £104,000 for “rural development” projects.

One of the documents relates to last year’s Agriculture (Retained EU Law and Data) (Scotland) Act. It is a letter sent by John Somers, Nicola Sturgeon’s principal private secretary, to Edward Young, the Queen’s most senior aide, in July last year.

In his letter, Somers asked the Queen to give her consent to the legislation – a requirement before it can be passed by the parliament – as it had the “potential to affect the Queen’s personal property and interests, and the hereditary revenues of the crown”. He pointed out that, for example, the bill could “result in an increase or decrease in the amount of subsidy that can be claimed”.

Somers added that the Scottish government would amend the bill to exempt the crown from being prosecuted over specific offences related to food quality, purity and labelling rules and the collection of farming data, say on pollution, animal health or climate. The bill does not exclude those who work for the Queen from being prosecuted.

Somers asked if the bill, and the planned amendments, were “acceptable” to the monarch. They were. Eight days later, Young, writing from Windsor Castle, confirmed the Queen was content to give her consent.

A Buckingham Palace spokesperson said: “The royal household can be consulted on bills in order to ensure the technical accuracy and consistency of the application of the bill to the crown, a complex legal principle governed by statute and common law. This process does not change the nature of any such bill.”

Related: Royals vetted more than 1,000 laws via Queen’s consent

There is no suggestion the Queen has ignored any legal controls that affect other private landowners or abused any of these legal exemptions. Critics argue that the secretive consent mechanism gives the monarch a unique right among Britons to approve proposed laws that could affect her private wealth.

She is one of Scotland’s largest private landowners, owning about 24,900 hectares (61,500 acres) at Balmoral and a further long lease on 4,730 hectares of Abergeldie estate, bordering Balmoral.

The Queen’s officials recently succeeded in getting the business rate valuations for all four of her grouse moors and “deer forests”, used by the royals for deer stalking at Balmoral, cut by 45%, from £45,600 to £25,500, backdated to 1 April 2017, using widely available appeal powers.

There are numerous businesses on the Balmoral estate: holiday cottages, “luxury” Land Rover tours, a nine-hole private golf course, salmon fishing on the River Dee, an estate restaurant, coffee shop and gift shop.

In the unlikely event Balmoral was suspected of staging a circus featuring tigers, lions or elephants – something now banned in Scotland – clauses inserted by ministers into the Wild Animals in Travelling Circuses (Scotland) Act 2018 mean the police are barred from searching the estate or circus vehicles without her consent. No other private land has that exemption.

Balmoral has been in the royal family’s possession since it was first leased by Queen Victoria in 1848. Under legislation passed in 1760 granting Britain’s monarchs a guaranteed income from the taxpayer through the civil list, the sovereign was forbidden from holding private property.

So when she decided in 1852 to buy the place, her husband, Prince Albert, did so on the couple’s behalf, helped by the Balmoral Estates Act passed specifically to allow it.

On Albert’s death in 1861, the then government again changed the law under the Crown Private Estates Act 1862 to allow Victoria to inherit Balmoral through a private trust. That legislation cannot be amended by the Scottish parliament, which controls every other facet of land ownership in Scotland, yet it gives legal authority for every monarch to buy other land in Scotland for their personal use.

Victoria’s successors to the crown have quietly expanded Balmoral by buying up neighbouring estates on at least five occasions over the last century. Prince Charles, known in Scotland as the Duke of Rothesay, will inherit the estate in turn when he succeeds the throne, without paying any inheritance tax.

Ever since Victoria and Albert transformed Balmoral into their favourite royal retreat, the estate has had totemic significance for the Windsors.

It was the stage for Victoria’s scandalising friendship with her personal attendant John Brown; it has given a Highland home to both the Queen Mother and now her grandson, Prince Charles, at Birkhall; Charles has mythologised a famous mountain on the estate with his children’s story The Old Man of Lochnagar; and the Queen’s worship at Crathie Kirk is an established part of the royal calendar during her annual summer holidays in Scotland.

It is also where the Queen entertains Scotland’s first ministers. Despite his anti-establishment credentials, Alex Salmond, the former Scottish National party leader, relished his weekend stays at Balmoral with his wife, Moira, taking breakfast with the Queen.

Salmond said before the 2014 referendum that Scotland would retain the Queen as head of state if the country voted yes to independence; the SNP, he said, supported the union of the crowns.

Nicola Sturgeon, his successor as SNP leader and first minister, is believed to be far less enthusiastic about the royals. Opinion polls find Scottish voters are more ambivalent, too, about the monarchy than in other parts of the UK.