The British women typhoid carriers who were locked up for LIFE in a mental asylum until the 1990s

They spent the best part of a lifetime at Long Grove Hospital - a mental asylum in Surrey - despite having none of the symptoms of the disease.

At least 43 typhoid carriers were taken into the asylum between 1943 and 1957.

Long Grove asylum in Surrey, where almost 50 women were incarcerated because they were typhoid carriers

Incredibly two of those women were still living in isolation rooms when it closed in 1992 - four decades after antibiotics which can counter the disease were developed.

The extraordinary tale of women consigned to life in the asylum in Epsom was uncovered by a BBC investigation.

Some former nursing staff believe that a number of the women may have been sane when they were admitted, but went mad because of their incarceration.

The original healthy typhoid carrier in the U.S, Typhoid Mary (right) poses with a nurse at one of the hospitals in which she was kept

Other patients with mental health problems may have deteriorated as a result of being kept in isolation.

Records show that only a few of the women admitted to the isolation unit were already in mental health hospitals.

More than half were admitted from private addresses and general hospitals.

Because some records are missing it is not clear how they may have been originally identified.

The women may have suffered from typhoid and recovered, but would have been tested to see if they were still carriers.

It is possible to carry the typhoid bacterium without suffering the effects of the disease.

In the early part of the last century it was common for hospital patients to be tested to establish if they were carrying typhoid.

All the women came from the London area - mostly the East End - with three new carriers each year entering the asylum in the 1940s and 50s.

That is a figure on a par with the total number of female typhoid carriers produced by the entire general population of London at that time.

Jeanie Kennett, a ward manager for 40 years at Long Grove, is certain that some of the patients she knew of were only detained at first because they were typhoid carriers - only to be driven mad by being locked up.

She said some of the women remained lucid.

She told the BBC of her memories, saying: 'When you spoke to them and they would start to relate about what they'd done when they were children and what they'd done when they were growing up and how they'd ended up in a place like a hospital - they longed for those years to be returned.'

She added it was a 'basic existence' for the women - some of whom were married with children or working when admitted.

'Life was pretty tough. It was prison-like - everything was lock and key,' said Mrs Kennett, who started working at Long Grove in 1955.

Of her patients she said: 'Everybody had forgotten about them. They were just locked away.'

The isolation unit itself closed in 1972, some women were transferred, but two were placed in bedrooms, isolated from the rest of the patients.

They had no visitors that staff can recall.

Mrs Kennett, now retired, said: 'These people were condemned to a life of isolation through no fault whatsoever of their own.'

Fellow nurse May Heffernan, a former ward sister who began work at the asylum in the 1960s, said all the women she had worked with had mental health problems.

She said the patients were well cared for and were taken out of the hospital on occasions.

But staff were reluctant to go inside the isolation ward and wore gowns and masks.

She added: 'We as a nation failed these people and we could have done better.'

Hugh Pennington, emeritus professor of bacteriology at Aberdeen University, said the women would only have posed a small risk.

'What happened to these women was not at all necessary,' he said.

'There was a big fear factor about typhoid, a bit like leprosy, they were locked up because it was the easiest thing to do.'

He said it appeared the women had simply been 'forgotten in the system'.

A spokesman for the Department of Health said: 'There was not, and never has been, a policy of incarcerating anyone, in this context.'

However, many of the women were incarcerated before the creation of the National Health Service.