Until last year’s restoration of the mock-Tudor well house, public access had rarely been permitted, and few of those who have lived in the vicinity for years have ever had the chance to take a look inside at what historians say is one of the best-preserved medicinal wells in the country.

Visitors were soon queuing up on Easter Saturday afternoon once Barnet Museum volunteers unlocked the doors to the historic well house in Well Approach, just a short walk from Barnet Hospital.

Pat Hicks, whose family home was opposite the wellhouse, said it was amazing to have had the opportunity at last to go inside a building that had always fascinated her as a child.

“In the 1950s the well house was always locked and barred. We used to play outside but it was forbidden to go inside. Mr Peck, who lived along the road and who had one leg, had the key, but we never saw him open the door.”

Ms Hicks had travelled back to Barnet from her home in Durrington, Sussex, after hearing about the open day.

Memories came flooding back for Barnet resident David Richards who also remembered playing in the gardens around the well house in the 1950s and 1960s when visiting a school friend in Pepys Crescent.

“I do seem to remember that one day the door was ajar, and we did peep inside, but it was all dark. This open day has been a real treat for me, and I agree with Pat that the restoration of the wellhouse is fantastic, its back to its original glory after being closed and vandalised for so long.”

Another Barnet resident was equally enchanted by the chance to marvel at the restoration of the well house and to take the twelve steps down to the well chamber.

“In my childhood in the 1960s we used to live nearby in Windsor Road and the well house was a mystery,” said Tony Swingler.

“It was always locked up and vandalised, so to see it fully restored underground, and to imagine what it must have been like in Samuel Pepys’ day, is amazing.

“Pepys would have walked along the lane from Wood Street, along what is now Wellhouse Lane and then up Well Approach; real Barnet history.”

Pepys was probably the most celebrated consumer of the Physic Well’s chalybeate spring water which was once fashionable to drink, and which attracted the gentry to the town.

Among the banners and artefacts on display inside the well house is Pepys’ coat of arms – one of the many historic banners to have been painted under the direction of photographer and historian, Geoffrey Wheeler.

Barnet Museum volunteers, led by Mike Jordan, former chair of the museum’s trustees, said the aim is to open up the well house on the third Saturday of every month once Barnet Council has finally agreed a fifty-year lease for the building and handed over the keys.

Mr Jordan escorted parties of eight people down the steps to the well chamber and took delight in describing all he knew about its history and the quality of the water which fills two tanks each about 17 inches deep.

The floor around the tanks is of old London bricks and the barrel roof of the chamber, although made of later bricks, was also thought to have resembled the original structure.

“We think the brick floor could be 600 years old and we hope to get a clue from the wooden plate to the original door. It’s drying out at the moment but once it has been dated, we might know more.

“The temperature inside the well chamber is a constant seven degrees, winter and summer, and the water tanks are filled by nearby underground springs.

“There is a report of the water being drunk in the 1940s – and it was said to be cool and sweet to the taste, reflecting the natural minerals in the water.

“There is quite a bid of sediment in the tanks and we hope to drain them to see what is down there.”

The original well house was demolished in the 1840s and all that remained on the surface was a small iron pump. The underground well chamber was finally re-opened in 1921 after the clerk to Barnet Urban District Council decided to check its condition.

Council workmen drained the backed-up water which had flooded the chamber and cleaned the steps to reveal what was described at the time as “an almost perfect example of an old physic well undisturbed.”

The mock-Tudor well house was constructed in 1937 to protect the dis-used well and its spring. After remaining closed and vandalised for decades, it was finally restored at a cost of £150,000, met by Barnet Council, a grant from Historic England and a donation from the Heritage of London Trust.