To colleagues, Edward Erin appeared to have the perfect existence — a glittering career as a doctor and clinical researcher and relationships with a string of glamorous young women.

But his bizarre double life was revealed last night after he was convicted of poisoning the drinks of his pregnant secretary to cause her to miscarry during their brief affair.

The respected consultant was carrying out ground-breaking research into treatment for asthma when police raided his offices at the Royal Brompton Hospital and at St Mary’s Hospital in West London in February last year.

He was also a lecturer and running a multimillion-pound property empire with his wife from their home in Kensington.

The raid was to lead to the untangling of his complicated personal life. Until then, his colleagues and patients had no idea that Erin, 44, was married with two children, while his closest personal friends knew nothing about his string of affairs.

Erin was the youngest of three sons of the chest consultant Lionel Erin and his wife Victoria. He took his medical degree at Cardiff University after graduating in pharmacology.

In 1990 he met a fellow student, Lowri Phylip, a microbiologist. From the start, Dr Phylip was aware that Erin had a secret life. Almost every weekend he returned home to Llandough, South Wales, but refused to allow her to meet his family.

The couple married in 2001 when Dr Phylip was three months pregnant but his parents did not attend the wedding and his wife met her mother-in-law for the first and only time the following January.

That occasion was the funeral of Erin’s sister, Catherine. Her death, as a result of anorexia at the age of 33, was to be a defining moment for Erin. Within months the ambitious young doctor had started an affair with a colleague that was to last five years.

He then began a relationship with another colleague, Malin Roesner, from Gothenburg, in Sweden, who was working at Northwick Park Hospital, in northwest London. The intense ten-month affair ended in October 2007 but the couple remained close.

Dr Phylip, 41, tolerated the mistresses as part of their “unconventional” marriage. “We were not like a couple doing everything together,” she said. “We always had separate lives but we loved each other. There were other relationships in the marriage, but it was the way it worked.”

Her husband explained: “The relationship with Lowri worked very well because we provided a stable and loving relationship to our two wonderful children and we were the best of friends.”

But his wife did not know of the affair with his 33-year-old secretary, Bella Prowse, which began at St Mary’s Hospital’s Christmas party in December 2007. Erin claimed that Ms Prowse, who had worked for him for five months, seduced him with the words: “Let’s have an affair”.

They spent many nights together over the next few weeks. They stayed at Ms Prowse’s flat in Tulse Hill, South London, his holiday house in Devon and at smart hotels in the capital, including one just 400 yards from Erin’s marital home.

He bought her a watch for her birthday, took her shopping at the designer stores in Kensington High Street and to fashionable restaurants. They exchanged hundreds of text messages.

Ms Prowse, originally from Totnes, Devon, was a party girl who loved nightclubs and smoked cannabis while Erin was a fitness fanatic who was passionate about mountaineering and climbing and despised smoking.

But Erin said that he thought he loved Ms Prowse. “She was supportive to me,” he said. “I told her things I do not usually talk about.”

There were rows, particularly when Ms Prowse, who had a 13-year-old daughter, discovered Erin had bought Dr Roesner a pair of pyjamas and when he mistakenly sent her a text message in which he invited his former lover away for a weekend.

It was as Erin was marking the anniversaries of the deaths of his sister and his mother that he received the news that Ms Prowse was pregnant. He pleaded with her to have an abortion, assuring her that he loved her and they could have children in the future.

Erin said he got anti-inflammatory drugs that induce abortion without intending to use them and only after discussing it with Ms Prowse. After some prevarication, Ms Prowse refused to go along with the abortion, explaining that it would be too traumatic. In 2002 she had a late-term surgical abortion, which left her suffering bouts of depression.

Ms Prowse became suspicious of her lover when she discovered powder in the bottom of a cup of tea the morning after she told him of the decision to keep her baby.

She told police that she also found bits floating in a cup of coffee bought by Erin the following week near St Mary’s Hospital, and in a bottle of orange juice he gave her at work.

Erin insisted that the powder in the tea was limescale from an old kettle and that he had put the crushed drugs in the cup of coffee to prove to Ms Prowse how unpleasant they are to taste in a bid to put her off.

He claimed that Ms Prowse must have put the pills into the orange juice, describing her as “a mad woman” who was plotting her revenge after discovering he was still in contact with Dr Roesner.

The GMC has already banned Erin from working directly with patients and is likely to hold a fitness-to-practise hearing to strike him off the medical register. As the consultant prepares for what is likely to be a lengthy jail sentence, he is also waiting for the results of the DNA tests that will reveal if he is the father of the baby.

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