He is said by The Sunday Times to have described the Queen Mother, of whom he was a close confidant, as a devoted Thatcherite who was more right-wing than other royals.

He wrote that the Queen Mother claimed the royal family used often to drink after-dinner toasts to Margaret Thatcher, whom he was also close to.

The Queen Mother: "Devoted Thatcherite"

But the diaries also record that one witness believed the Queen went out of her way to be unpleasant to Baroness Thatcher when she was prime minister.

Lady Mary Coleman, a niece of the Queen Mother, told Wyatt in 1986 that the Queen and other royals were "beastly and horrid" to Lady Thatcher during a trip to Balmoral.

However, the Queen told a former private secretary she got on "all right" with Lady Thatcher "but like all prime ministers she won't listen".

The Queen Mother is said to have been angry when reports in 1986 quoted palace sources as saying the Queen was critical of many of Lady Thatcher's policies.