Dr Lucy Dawson, 45, allegedly tweeted that she was getting "a stupid amount of dosh" and earning "megabucks" by working elsewhere while on sick leave from her hospital. She was reported to the NHS fraud hotline by her boss, Dr Nick Jenkins, after their 13-year affair ended "acrimoniously", a court heard.

It is alleged that Dr Dawson was working at other hospitals while on sick leave from an accident and emergency unit of Royal Gwent Hospital in Newport, South Wales, where she worked with Dr Jenkins, 56. In one of Dr Dawson's tweets she allegedly wrote that her way of life was "night shift Monday, debauchery Tuesday" after getting her extra pay.

But the wife of her former lover, Marianne Jenkins, 53, spotted the tweets and "flagged them" up to her husband.

Dr Jenkins, a consultant in emergency medicine, told Newport Crown Court: "I knew she was on sick leave and I heard she had been working at another hospital. My wife showed me Twitter pages with Lucy Dawson's comments on them.

"These were fully accessible to the public and showed up using an ordinary internet search. I felt I had a professional obligation to deal with this so I called the fraud hotline."

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Dr Jenkins was Dr Dawson's line manager from 1994 until 2006 and the pair were having an affair for most of that time. The court heard that the relationship was "a well-known matter" at the Royal Gwent hospital, and that the break-up was "acrimonious".

Dr Jenkins, a father of five, said he did not personally access his ex-lover's Twitter account. He told the jury: "It was an acrimonious split and afterwards myself, my wife and my wife's family began receiving unwanted communications from Lucy Dawson. My wife would look at her tweets to see if we could expect any more unwanted communications. She would do it to gauge her mindset."

"My wife said to me: 'Look it's on Twitter that she's working elsewhere.' "

A mother of two, Dr Dawson is accused of claiming £29,320 in sick pay when she was off work with stress, while at the same time earning £7,840 working as a stand-in doctor.

Health chiefs began an investigation after the phone call from Dr Jenkins. Carl Harrison, prosecuting, said: "While on fully paid leave she worked 10 shifts at hospitals in Worcester and Hereford, earning £7,840.

"She was signed off from work with stress and depression but went on to the social networking site Twitter.

"She said she was earning megabucks and a stupid amount of dosh.

"She also tweeted about drinking wine and other things such as 'night shift Monday, debauchery Tuesday'," he said.

He added that, as well as paying Dr Dawson £29,320 to cover her sick leave, the health board had to pay about £36,000 for locums to fill her role.

The court heard that Dr Dawson also tweeted about her employer, the Aneurin Bevan Health Board, for which she had worked since 1989.

Her tweet allegedly said: "They lie and bully people."

The court heard that Dr Dawson added that she couldn't work for people she "wanted to kill".

Alun Jenkins, for Dr Dawson, insisted that she was genuinely depressed and stressed by "poisonous issues" in the accident and emergency department. He described her as a "whistle-blower" who had raised complaints about colleagues failing to carry out their jobs properly.

Dr Dawson, of Monmouth, South Wales, has since resigned from Royal Gwent. She denies two charges of fraud. The trial continues.