The fiance of best-selling children's author Helen Bailey has been jailed for life for murdering her to get his hands on her £3.5m fortune.

Ian Stewart, 56, suffocated the wealthy widow after secretly plying her with a sleeping drug and then dumped her body in a cesspit.

He then reported her missing from their £1.5m home in Royston, Herts, telling police she had told him she was going to her holiday cottage in Broadstairs for some space.

Her body was found three months later. He later claimed two men called Nick and Joe kidnapped her.

But a jury of seven men and five women took around five-and-a-half hours to find "devious killer" Stewart guilty of the "cynically executed murder that had money as its driving motive".

Today, Judge Andrew Bright QC sentenced him to life in prison with a minimum term of 34 years. Stewart refused to appear in court for the sentencing.

The judge said Helen's murder was planned "well in advance" and described him as a "real danger for women".

But addressing him in his absence, Judge Bright said: "Ian Stewart, you've been convicted after a trial of murdering your fiance Helen Bailey who was excitedly making arrangements for your wedding while you were planning how to kill her, hide her body, and explain her disappearance.

"She was so devoted to her dog Boris that you decided you must also kill him.

"Helen was only 51 and at the height of her success as a writer when you brought her life to a cruel end and dumped her body in a foul smelling cesspit for her body to decompose.

"In a few hours of her murder you used your knowledge of her financial affairs and your compute expertise to change a standing order.

"You planned her murder well in advance and secretly administered Zopiclone tablets to her so you could smother her when she was too drowsy to fight you off.

"You then set about attempting to deceive the police and Helen's family and friends that she had left you a note, needed some space and did not want you to contact her.

"You persisted in that callous lie for three months, repeating it to anyone and everyone.

VIDEO: Ian Stewart has been jailed for Helen Bailey's murder

"You knew Helen to be a wealthy woman but were not content to share her wealth. She had assets of more than £3 million pounds."

Judge Bright continued: "The sentence for murder is fixed by law and is for life imprisonment.

"That is the sentence I impact upon you, but I also must consider the minimum term before you are released on licence.

"I am of the opinion that you serve a real danger for women you form a relationship with.

"When you serve the minimum term, it will be down to others to decide whether to release you.

"The seriousness of the offence is not so high as to justify a whole life order.

"However, the appropriate starting term for a minimum term is 30 years."

"Helen was only 51 and at the height of her success as a writer when you brought her life to a cruel end and dumped her body in a foul smelling cesspit for her body to decompose" - Judge Andrew Bright QC, to Stewart

Judge Bright told the court the degree of planning which went into Ms Bailey's murder along with the deception of everyone involved were two aggravating features.

He said: "There are two aggravating features in this case which increase the seriousness of your offence.

"The significant degree of planning, and the fact you went to considerable lengths to conceal the bodies of Helen and her dog in the hope they would eventually decompose and never be found.

"You also deceived Helen's family and friends by a calculated and callous series of lies, they had to deal with the misery of not knowing her whereabouts or her fate.

"I have read the impact statement of Helen's brother John, in which he sets out the effect the cruel murder of his sister has had on him and his family.

"His family all feel an immense outrage. As John observes, the world has lost a gifted author and the family will have to live for the rest of their lives with the deep sense of loss.

"Whilst we will never know whether you had an additional motive for killing a woman who loved you and wanted to be your wife, this is a murder for gain with aggravating features which make it difficult to think of a more heinous crime.

"I sentence you to a minimum term of 34 years. I acknowledge you will be 90 years of age before you become eligible for parole, but I am not inclined to reduce the minimum term in light of your age."

The jury yesterday unanimously found Stewart guilty of murder, one count of fraud, preventing lawful burial, and three counts of perverting the course of justice following a six-week trial.

St Albans Crown Court was told Stewart fabricated a story that Ms Bailey had left a note saying she needed time and space and was heading to their holiday cottage in Broadstairs.

But after being arrested, computer software engineer Stewart hatched a plan that two mystery men called Nick and Joe kidnapped Ms Bailey and blackmailed him for £500,000.

The court heard the men were business associates of Ms Bailey's late husband John Sinfield, and kept Stewart at their mercy and swore him to secrecy.

But the prosecution said Stewart used two old friends, Joe Cippullo and Nick Cooke, as inspiration to create an image of the 'kidnappers' who were shown to the jury.

It was heard Stewart killed Ms Bailey to be in line to gain two homes, enough cash to ensure a "very comfortable" lifestyle, pension and life insurance payments from his fiancee.

The court heard on the day Ms Bailey was killed on April 11 last year, she had been using her iPad to search for venues for their wedding which was planned for September.

Her body was dragged to the garage and dumped in the cesspit along with her beloved dog Boris, a dog's toy, a couple of bin bags and a pillow slip which the court heard could have been used to smother Ms Bailey.

On the same day Stewart was seen at Royston Recycling Centre disposing of a large white item, believed to be a duvet which he used to drag her body to the pit.

He revisited the tip days later to ensure the duvet was gone, and reported Ms Bailey missing at 3.37pm on Friday April 15 last year.

Stewart also used his own computer to change a standing order from Ms Bailey's bank account to the couple's joint account from £600 to £4,000.

He then acted out a "complicated charade" that Ms Bailey had left a note saying she needed time and space and was heading to their holiday cottage in Broadstairs.

The father-of-two sent numerous text messages to her phone "leaving a trail" which prosecutor Stuart Trimmer QC said would "give the impression of somebody whose lover had just disappeared".

Mr Trimmer said Stewart "might have got away with it" if he hadn't taken Ms Bailey's phone to Broadstairs days after she was reported missing.

Her mobile phone connected to the router at the cottage, after Stewart told police Ms Bailey had disappeared and she had taken her phone with her.

Ms Bailey's mobile phone has never been found.

Stewart admitted continuously lying to Ms Bailey's family and police as they carried out a 'futile' missing person investigation after he fabricated a cover story she had ran away.

In the months before she died she had been searching online for things such as "falling asleep in the afternoon" and "can't stop falling asleep".

Analysis of Ms Bailey's hair revealed she had been administered sleeping drug Zopiclone from as early as February 2016.

Consultant forensic pathologist Nat Cary told the court Ms Bailey could have been killed in a sleeper-hold but the formal cause of death was undetermined.

Her body was found with no broken bones or signs of a violent assault in the cess pit she once said in banter was a "good place to hide a body".

At the time of her death, Ms Bailey was said to have had assets worth £3,326,316.

The couple had met on a website which was for people dealing with grief after Stewart's wife Diane died in 2010.

In Ms Helen's book released in 2015, When Bad Things Happen in Good Bikinis, she spoke of the grief of losing her husband John who drowned in front of her while in Barbados.

She also spoke of how she had dramatically once told her husband John she was "going to disappear", vanish and start a new life under a new identity.

It also detailed a relationship with GGHW – Gorgeous Grey Haired Widower– who was Stewart, and also dedicated the book to him.

She wrote "Ian Stewart: BB, I love you. You are my happy ending."