AN obsessed woman who carried out an online stalking campaign against the Holby City actress Rosie Marcel has been jailed for two-and-a-half years.

Sarah Rumbelow, 21, became completely obsessed with Miss Marcel, who lives in St Albans and plays consultant cardiothoracic surgeon Jac Naylor in the hit BBC drama series.

But the obsession took a sinister turn when throughout 2011 Rumbelow began sending the actress hateful emails, tweets and communications via chat rooms.

To do so, she set up bogus addresses and thought she had covered her tracks.

Some messages sent to the actress threatened to kill her, others warned she would be raped.

But after the victim called in the police, detectives were able to establish Rumbelow was behind the sick messages.

On Friday Rumbelow, of Brockley in South East London, appeared at St Albans crown court to plead guilty to a charge of putting a person in fear of violence by harassment.

The charge specified that between January 1, 2011, and last autumn she posted threats to harm or kill Rosie on social network sites and sent threats by email and in letters.

Rumbelow also appeared for sentence in breach of a judge’s restraining order not to contact the actress.

The 36-year-old married actress, who has helped the St Albans day hospice Grove House with fundraising in recent years, is the daughter of television director Terry Marcel and sister of writer and actress Kelly Marcel.

Simon Wilshere, prosecuting, told the court on Friday that the actress had received hateful communications during 2011 threatening her with both violence and sexual violence.

He said there was “an element of concealment” in the way Rumbelow had sent the communications because she had set up a variety of bogus accounts so her real identity would not be revealed.

Despite that, Herts Police were able to track her down and she was arrested last October and remanded in custody after masses of newspaper clippings and articles about the actress were found at her home .

In May of this year Rumbelow appeared in custody before Judge John Plumstead to plead guilty to the charge of harassing Rosie.

By then it had been discovered she suffered from ADHD and Asperger’s Syndrome.

The judge adjourned sentence so that Rumbelow could be assessed to see if she was suitable for treatment for her problems and a non-custodial sentence. He granted her bail and made a restraining order that she was not to contact the actress.

But after being released from custody, Rumbelow immediately set about sending the actress spiteful messages including one to her sister which said “Your sister is finished. Rosie will get hers soon. Watch this space.”

On Friday the court was told Rumbelow had again tried to cover her tracks and when arrested attempted to shift the blame onto someone else.

Alex Radley, defending, said Rumbelow had “clear health issues” and asked the judge to consider passing a suspended sentence because treatment was available for her in the community.

Judge Plumstead said: “This is a disturbed person’s crime, but it can’t be said she is free of blame.”

Passing sentence he told Rumbelow: “I don’t doubt that you are a young woman who has significant difficulties.”

But, he said, her problems had not reduced her understanding that what she was doing was wrong.

He jailed her for two and a half years but told her the time she had spent in custody, a total of some nine months, would count towards the time she serves.

Rosie Marcel was in court for Friday’s sentence.

As she left the court with a friend, she said: “It was a just sentence. Now I just want to get on with my life.”