Simon Bews, 43, of London Road, Sleaford grabbed the girl's bottom after dragging her into the road and putting his hand over her mouth in the late night attack.

Bews, a married father-of three, admitted sexually assaulting the girl in George Street, Sleaford.

Judge Michael Heath at Lincoln Crown Court said: "This girl thought she was going to be raped.

"What makes this case a very serious sexual assault are the circumstances in which you did it - she was a 17-year-old girl walking alone late at night."

He was also ordered to register as a sex offender for life and was banned from working with children.

Bews, who was a director with Winkworths estate agents for over 15 years, was returning to his £400,000 home, after a drunken night out when he began following the girl.

John Dee, prosecuting, said the girl had also been out with friends in Sleaford and been walking home alone after a row with her boyfriend when she noticed Bews following her.

He said: "She was sufficiently concerned to ring her boyfriend and tell him that a man was following her.

"While she was on the phone the assault took place, she describes it as lasting two to three minutes.

"He came up behind her and grabbed her in two ways; one arm across her shoulder and over her mouth, the other grabbed her buttocks forcibly.
"It was a persistent grab, a forceful grab.

"She was dragged into the road, her mobile phone was taken off her and she screamed."

The court heard Bews only fled when the girl's boyfriend arrived at the scene.

In a victim impact statement the girl said she thought she was going to be raped and was petrified.

She has not been out in Sleaford since the attack in November last year, the court heard.

Mr Michael Cramner-Brown, mitigating, said it was a 'complete aberration' by Bews.

He said: "He finds it impossible to comprehend why he did what he did."

He said despite being a director, Bews had financial difficulties with a large mortgage and fees for his son's private drama school in London.

Speaking outside court with her mother the girl said: "We are happy with the sentence.

"He deserves everything he gets. He is not the nice man they try to make out he is in court - we could not believe what they were saying about him."