Lifesaving breast cancer screening work in Norfolk has been put in jeopardy by vandals who have wrecked mobile units by shooting them with air rifles and smearing them with oil and tar.

Lifesaving breast cancer screening work in Norfolk has been put in jeopardy by vandals who have wrecked mobile units by shooting them with air rifles and smearing them with oil and tar.

Three Norfolk and Norwich University Hospital screening vans have been targeted by vandals who have broken windows with air rifles, damaged electrical cables and even set-off fireworks inside electrical units.

The vans' steps have been coated in oil, grease and tar which could cause women to fall as they enter the centres to be screened.

Yvonne Pointer, a breast radiographer, said: “We are appalled that this kind of mindless vandalism is being targeted at an NHS cancer screening service.”

The vans have had to be taken out of service for long periods of time while the damage, which also includes offensive graffiti and stolen signs, is fixed.

Women have the best chance of overcoming the disease if the cancer is spotted and diagnosed early.

“We provide a very important local service for women and these types of attacks have become much more common over the past couple of years. Our mobile units move around the county and they are often in one location for weeks at a time so it's not practical to bring them back to Norwich every day,” said Ms Pointer.

The attacks have been concentrated in South Norfolk, including Harleston, Attleborough, Diss with the latest attack in Long Stratton on the weekend of November 17.

Breast screening is a method of detecting breast cancer at a very early stage.

The first step involves an x-ray of each breast, a mammogram, which can detect small changes in breast tissue which may indicate cancers which are too small to be felt either by the woman herself or by a doctor.

The NHS Breast Screening Programme provides free breast screening every three years for all women in the UK aged 50 and over.

About 1.5m women are screened in the UK each year.