Michael Lane, was convicted of Shana Grice's murder and has been sentenced to life imprisonment.
The jury took only two hours to convict the 27-year-old of murder after their deliberation on Wednesday.
Miss Grice, 19, was found with her throat slashed in her smoke-logged bedroom at the bungalow she shared with two housemates in Brighton.
Lane waited until she was home alone before murdering her last August 25 after she decided to rekindle a relationship with her ex-boyfriend, Ashley Cooke.
Sentencing Lane at Lewes Crown Court, Mr Justice Green said he would serve a minimum of 25 years.
“We are very relieved that the man who killed our precious Shana, our only child, will serve a long and deserved prison sentence. Michael Lane is a dangerous and obsessive man. The police and prosecution had statements from other girls to whom Lane had in the past shown similar controlling behaviour. These witnesses came forward after his arrest but were not permitted to be called at trial for evidential reasons. Lane showed his arrogance and cowardice at trial by pleading not guilty in the face of overwhelming evidence. In his contemptible defence he sought to blame innocent men for his actions. He compounded this by relying on the wholly inadequate police assessment of risk to Shana to suggest he was no danger to her."
The man found guilty of murdering Shana Grice will be sentenced at Lewes Crown Court this morning.
Michael Lane attacked his former lover in Brighton last August - just five months after police fined her for wasting their time when she complained about his stalking. He was found guilty yesterday.
This is the first photo of the man who is believed to have been the attacker in a terrorist incident in Westminster.
The man is shown on a stretcher receiving medical treatment. In the image, weapons that are believed to be knives have been circled in red.
The moment shots were fired outside Parliament was caught on camera.
The footage shows people rushing out from the grounds before three shots ring out.
Two people are confirmed to have died after a knifeman brought terror to the heart of Westminster before being shot by armed officers.
A woman died as the attacker drove across Westminster Bridge and a police officer stabbed at the Houses of Parliament has also died.
Police have apologised to the family of murdered teenager Shana Grice saying they may not have done "the very best we could" to protect the teenager whose throat was cut by Michael Lane.
I would like to extend my sincere sympathies to the family and friends of Shana Grice, who was murdered by Michael Lane.
When we looked at the circumstances leading to Shana’s murder, we felt we may not have done the very best we could.
Within days of her murder I personally visited Shana's family to apologise on behalf of Sussex Police and we made a referral to the IPCC.
The referral was specifically in relation to how we dealt with incidents involving Shana leading up to her murder.
Since then we have thoroughly reviewed all aspects of how we deal with cases of stalking and harassment and, working with partners, we have now taken on the learning and our approach is more robust.
We are fully cooperating with the IPCC and until we receive their report we cannot comment further."
Teenager Shana Grice was murdered at the hands of an obsessed stalker -her jilted ex-boyfriend Michael Lane.
She was found with her throat slashed in her smoke-logged bedroom at the bungalow she shared with two housemates in Brighton, East Sussex
Lane, 27, was found guilty at Lewes Crown Court of murdering Miss Grice in the bedroom of the bungalow she shared with two housemates in Brighton last August 25.
He waited until she was home alone before murdering her last August 25 after she decided to rekindle a relationship with her ex-boyfriend, Ashley Cooke.
Her devastated mother Sharon has spoken out saying her daughter's murdered could have been prevented if police had listened to her fears.
Sharon Grice criticised police for not taking her 19-year-old daughter Shana Grice seriously before she was killed.
Mrs Grice said the family "instantly" knew Lane was responsible as he had been "harassing and stalking" her for the past year.
Officers received at least four complaints about mechanic Lane's behaviour towards Miss Grice in the months before he fatally slashed her throat.
We brought Shana up to respect authority and to always respect the law.
We firmly believe her murder could have been prevented if her fears had been listened to and taken seriously by the police."
A witness has said he saw a man stab a policeman with a "big knife" in Westminster.
Rick Longley told the Press Association: "We were just walking up to the station and there was a loud bang and a guy, someone, crashed a car and took some pedestrians out.
"They were just laying there and then the whole crowd just surged around the corner by the gates just opposite Big Ben.
"A guy came past my right shoulder with a big knife and just started plunging it into the policeman.
"I have never seen anything like that. I just can't believe what I just saw."
Judge Sheridan remarked that, on several occasions, Thames Water managers ignoredwarnings and "risks identified by employees and others.
What a dreadful state of affairs that is. Logbook entries reflected the pathetic state of affairs and the frustration of employees.
Thames Water utilities continually failed to report to the Environment Agency despite (managers) being fully aware of the issues and reporting governance.
There is a history of non-compliance.