With a two-bar electric fire in the Balmoral library and Cornflakes in Tupperware containers, the Queen has a thrifty approach to running a palace.

But while her frugality is admirable by modern standards, her Tudor forebears would have been dismayed by the lack of pomp, according to the former curator of Historic Royal Palaces.

"Elizabeth I and Henry VIII would be absolutely appalled because, unlike our queen, they lived in a very public environment," said Simon Thurley.

Meals and ablutions were conducted in front of an audience in Tudor times, he explained, "so there was a necessity to maintain status, magnificence, dignity in a way that our queen - very fortunately for her - doesn't have to do".

He added that the Queen's thriftiness is "a generational thing, rather than anything to do with being monarch".