John Nutting, for the prosecution, said that Michelle Taylor was infatuated with John Shaughnessy, aged 28. Their affair had begun before his marriage but he told her he would never leave his wife Alison, so she plotted with her sister Lisa to kill Mrs Shaughnessy.
They waited for the 20-year-old bank clerk outside her flat in Vardens Road, Battersea, south- west London, on 3 June last year.
Mr Nutting said: 'They gained access to the flat on some pretext and there, on the top of a flight of stairs, Alison was stabbed to death.' A post mortem examination showed that Mrs Shaughnessy had been stabbed 54 times. Ms Taylor, 21, and her 18-year-old sister Lisa, of Kemble Road, Forest Hill, south-east London, have both denied murder.
Mr Nutting said Mr Shaughnessy worked at the Churchill Clinic in Lambeth, south London, with Ms Taylor.
He said: 'Some time before he became engaged to be married to Alison he and Michelle began to have an affair. That affair continued after his marriage. Michelle became completely infatuated by him . . . She knew he would never leave Alison. He told her so.'
Mr Nutting said that after Mrs Shaughnessy was murdered, the sisters returned to the clinic and Ms Taylor gave Mr Shaughnessey a lift home.
Mr Nutting said: 'He discovered the body of his wife lying where Michelle and her sister had left her body when they murdered her a few hours earlier.'
After Mr and Mrs Shaughnessy were married in 1990, Ms Taylor maintained a pleasant front with Mrs Shaughnessy, cultivating her company and accompanying the couple to pubs, to preserve her relationship with her lover.
Mr Nutting said Mrs Shaughnessy 'became somewhat vexed (about her husband's relationship with Ms Taylor) but, unworldly and immature, she did not suspect the true nature of their relationship or the true feeling Michelle harboured for Shaughnessy. She trusted the man she was to marry'.
He added: 'But the reality of Michelle's feelings for Alison were very different.'
Michelle's true feelings of 'suppressed jealousy and hatred for her rival' were disclosed in her diary. One entry read: 'I love him being with me and for a long time all I have wanted was for him to sleep the night so I had him to hold.'
In another entry Ms Taylor complained that Mr Shaughnessy always rushed off after they made love.
In October 1990, Ms Taylor writes: 'I hate Alison, the unwashed bitch. My dream solution would be for Alison to disappear as if she never existed and then maybe I could give everything I wanted to the man I love.'
After discovering Mrs Shaughnessy's body with Mr Shaughnessy, Mr Nutting said Ms Taylor 'affected horror and shock'. She went into a pub shouting hysterically: 'Please phone the police; my friend has been killed.'
The trial was adjourned until today.Reuse content