Women living downwind from nuclear power plants are at five times greater risk of developing breast cancer, experts have warned.

In three separate studies, a team of scientists looked at the rates of various cancers in populations living close to Trawsfynydd power station in North Wales, Bradwell in Essex and Hinkley Point in Somerset.

They discovered breast cancer rates, in particular, were higher than expected national averages at all three sites.

At Trawsfynydd, rates of the disease were five times greater than average, while in Essex and Somerset women had double the risk of developing breast cancer.

Women under the age of 60, who live downwind from the Trawsfynydd nuclear power station in North Wales (pictured) are at five times greater risk of developing breast cancer, experts have warned

Researchers assessed the rates of various cancers at three nuclear sites including Trawsfynydd (above), which ceased operation in 1993, as well as at Bradwell power station in Essex and Hinkley Point in Somerset

The research, supervised by Dr Chris Busby, who was previously based in Aberystwyth but is now attached to the Latvian Academy of Sciences in Riga, also found other types of cancer were recorded at double the rate in Trawsfynydd.

The Welsh plant is the only nuclear power station built inland in the UK.

It acts as a cooling water source and is also a sink for radioactivity released from the plant.

A significant amount of radioactive material exists in the lake bed sediment.

The power station ceased operation in 1993 but has yet to be fully decommissioned.

The prevailing winds at the site are south westerly and more than 90 per cent of those living downwind of the power station were surveyed by researchers working for Dr Busby.

The paper, published this month by Jacobs Journal of Epidemiology and Preventive Medicine, states: 'Trawsfynydd is a "dirty" nuclear power station.'

'As it has carbon dioxide, gas-cooled graphite block reactors, its releases into the air are higher than most other types of nuclear reactor.

At the Essex and Somerset power plants breast cancer, pictured, rates were found to be twice the national average

'In addition, all the liquid releases are discharged to the lake, where they have accumulated to the lake body sediment,' the researchers noted.

'Results show very clearly that the downwind population has suffered because of these exposures.

'This is most clear in breast cancer in the younger women below 60, where the rates were almost five times the expected.

'Additionally we see a doubling of risk in those who ate fish from Trawsfynydd lake, which supports the conclusion that it is mainly a nuclear power station effect that is being seen.'

Other forms of cancer showing elevated levels included prostate, leukaemia, mesothelioma and pancreas.

Altogether, 38 people in the area researched were diagnosed with cancer between 2003 and 2005, against an 'expected' level of 19.5.

The report said: 'These results are remarkable and relevant to political decisions about nuclear energy.'

In a separate report, also published in the Jacobs Journal of Epidemiology and Preventative Medicine, Dr Busby's team revealed their findings of a similar study close to the Bradwell nuclear plant in Essex.

The plant is located on the south side of the River Blackwater in Essex.

In order to arrive at their conclusions they compared populations in wards adjacent to the River Blackwater with a control population living nearby in an uncontaminated area close to the River Crouch.

The researchers concluded: 'Between 1995 and 2001 breast cancer mortality was significantly higher in wards adjacent to the River Blackwater in Essex than in wards which were inland.

'The Blackwater wards which had measured radioactive contamination from the Bradwell nuclear power station had about twice the breast cancer mortality than a control group of wards on the uncontaminated River Crouch.'

The researchers concluded: 'These results are remarkable and relevant to political decisions about nuclear energy.' Pictured, breast cancer under the microscope

They added: 'We have also studied breast cancer mortality in the wards near the Hinkley Point nuclear site in Somerset, using the same approach as this study, and have found the same result, a doubling of risk.'

All three nuclear power plants are managed by Magnox Ltd, a company owned by the Nuclear Decommissioning Authority, which is 'responsible for the decommissioning and clean-up of the UK's civil nuclear sites on behalf of the Secretary of State for Energy and Climate Change'.

A Magnox spokesman said: 'Comment on the details of the study is a matter for experts in public health.

'However the radiation exposures of our workforce, and that of the general public, from authorised discharges from the nuclear industry, are well below the maximum levels authorised by independent regulatory bodies.

'The limits are set to ensure members of the public are properly protected.'

A spokesman for the UK Government's Department for Energy and Climate Change said Public Health England

Dr Jill Meara, director of Public Health England's Centre for Radiation, Chemical and Environmental Hazards (CRCE), said: 'Identification of disease clusters are matters for local public health teams.

'If those teams needs specialist support, such as in radiation epidemiology, they can talk to CRCE for assistance.'