The woman was alone in her home in Ashby de la Zouch, Leicestershire, enjoying her 79th birthday when the thieves struck.

The woman allowed one of the thieves into her home when he said he was from the gas board.

Her son, who asked not to be identified, described the theft as "cruel".

The thieves must have seen the birthday cards, yet still committed the crime Detective Constable Sammy McIlroy

"I am utterly and totally appalled by the cruel, callous nature of these moronic individuals.

"They have duped a terminally ill, elderly lady on her birthday into letting them into her house, where they stole all of the money she had saved to pay for her winter bills due this month."

The first thief produced fake identification and asked if he could make some checks.

He inspected gas appliances in the kitchen before asking the victim to wait while he checked other appliances.

He then entered the living room and stole a large amount of money from the woman's purse.

Detective 'sickened'

He was joined by an accomplice outside, police said.

Detective Constable Sammy McIlroy, of Coalville CID, said he was "sickened" by the theft.

"The thieves must have seen the birthday cards, yet still committed the crime."

The first suspect is described as a white man, aged about 29, 5ft 10ins with short, straight black hair and an Irish accent.

The second man was also white, aged around 30, 5ft 10ins and of stocky build.