Her family want to trace former colleagues who can confirm the nature of the work performed at the factory which would have brought Mrs Llewellyn into contact with asbestos dust.

Her son, John Frost, aged 52, who lives in Ronaldsway Drive, Newcastle, said: "Mum started feeling unwell about five years ago and she went to see a specialist who diagnosed her with cancer caused by asbestos.

"We checked through her employment history and the factory in Butt Lane was the only place where we thought she could have been exposed to asbestos.

"She was given less than 12 months to live but she fought it tooth and nail and ended up living just short of six years, which amazed the doctors.

"Mum hadn't had the best quality of life over those six years and the last year had been particularly difficult for her.

"The disease mum died from was no cause of her own. She lived a very healthy and clean lifestyle and didn't smoke or drink.

"Before she passed away she was a bit disillusioned that no-one had taken responsibility for her catching this awful disease and she insisted we kept on asking and pushing for answers."

There are a variety of conditions which are thought to be caused by inhaling asbestos and they can take many years to develop. Mesothelioma, which Mrs Llewellyn suffered from, is an aggressive cancer which most commonly occurs in the lining of the lungs and is extremely rare in the absence of asbestos exposure. Symptoms typically start with breathlessness and chest pain and the condition is often associated with a rapid and significant weight loss and heavy and sudden sweating, typically at night.

Daughter-in-law Linda Frost, aged 49, said: "We've been campaigning for five years now but no-one seems to want to know. The Government has started handing out compensation to asbestos sufferers in some cases and Helen was writing a letter to the Prime Minister but unfortunately she was too unwell to finish it. We need her old workmates to come forward and tell us what kind of work Helen used to do so we can take this forward."

The family's solicitor, Helen Childs said: "We need to locate former colleagues who can confirm the nature of the work performed at the Butt Lane factory which would have brought her into contact with asbestos dust.

"Witnesses who worked alongside her husband, John Frost, are also sought. He worked in the building trade and worked for many large firms including Wimpeys. He also worked at Tunstalls in Burslem."

Former colleagues of Mrs Llewellyn can contact Ms Childs at hchilds@boyesturner.com or call her on 0800 884 0718.