Seven million people visit Hampstead Heath every year, but only a few have unpicked its hidden secrets.

In a casual stroll on London’s largest open space you might unwittingly see the legacy of hundreds of years of history, with what is rumoured to be the burial ground of Queen Boadicea, the ruins of a home which sheltered a nerve-racked prime minister and the parade ground of Hampstead’s volunteer army.

One man who has combed every nook and cranny of the beauty spot is Michael Welbank, deputy chairman of the City of London Corporation’s Hampstead Heath Consultative Committee.

One of the tales that makes Mr Welbank chuckle concerns Jack Straw’s Castle and how the now luxurious flats were built as a vengeful joke.

In the 1960s when Raymond Erith, a specialist in building beautiful country houses, took on the project, his plans were met with fierce opposition by a Hampstead community which scoffed at his designs.

“Erith was good friends with the hoi polloi in the home counties and he was appointed to build this pub,” recounts Mr Welbank.

“But when he started work it met with such furious opposition from the licensing authority, the police authority and the local community, that he built it as a joke.

“He thought, ‘Bugger you, I am going to build it in wood’. He wrote in his diaries that this pub was going to be the ugliest building in Hampstead and now it’s a listed building, when it was originally condemned by the old Hampstead society.”

Although Hampstead is synonymous with well-heeled artists and playwrights, Mr Welbank notes that the village has never had strong ties with royalty.

But on the few occasions when the monarch of the day has scaled Hampstead’s hill, they have not always been happy sorties.

Mr Welbank, who lives in Belsize Park, said: “When William IV came up to Hampstead in 1835 for a strawberry tea, he had with him this great procession which passed by Whitestone Pond, but the whole thing was overshadowed somewhat when a footman was run over and killed.

“It did put rather a downer on things, with a huge crowd up there to welcome him.”

George III had a similarly unfulfilling visit to what is today known as Pitt House.

Prime Minister William Pitt suffered from a nervous disposition and often retreated from public life. On one such occasion he had been offered refuge at a mansion on the Heath, where he stayed for several months.

“He was a total recluse in his time there. He spoke to no-one and had his meals taken to his room,” said Mr Welbank.

“It got very embarrassing for the King, with his prime minister disappearing.

“He was a little aggravated and sent messages to Pitt and it’s alleged that the King drove out from London and asked to see Pitt. Pitt is said to have refused to see him, which is hilarious when you think about it.”

Mr Welbank, a retired architect, has travelled all over the world, but the lure of the Heath always brings him back and he has lived his entire life around the beauty spot.

“When I was six or seven my family treat was to be taken on Sunday for tea at the brew house in Kenwood,” recalls the 83-year-old.

“I thought it was magic. When I was a schoolboy we used to have cross country races across the Heath. It has been my backyard all my life.”