Norfolk police officer James Curtis (37) also smashed up a sex toy belonging to Donna Brand, emptied every cupboard in her house, turned the heating up to 30C and emptied her freezer.

Curtis, of Marsh Road, Terrington St Clement, had already left her terrified with his "possessive and controlling behaviour" during their time living together, Lincoln Crown Court was told.

He regularly attacked her, threatened suicide and boasted that his ex-wife was visiting him in secret to indulge in sex acts in the garage, a jury heard.

Curtis and Ms Brand first met in 2004 while both were working as police officers at the Terrington Beat Base in Terrington St John.

Curtis had recently split from his wife, and by spring 2005 the pair were living together – first at his parents' home and later in Holbeach.

Giving evidence yesterday, WPC Brand told how Curtis tormented her with "mind games" before launching a revenge attack when she dumped him.

The court heard she was "head-over- heels in love with him" but he was possessive and controlling and aggressive when he was in drink.

Michael Cranmer-Brown, prosecuting, said Curtis was on medication for depression after being involved in a car crash and could be "volatile and somewhat unstable".

'jekyll and hyde'

"When his medication was combined with drinking his character changed and he was something of a Jekyll and Hyde," he said.

In November 2005, Ms Brand was driving home from a visit to the seaside when Curtis threatened to throw himself out of the car.

Mr Cranmer-Brown told the court: "There was a lorry behind them.
"He said: 'I'm going to do it now.

"Even if we're going slow the truck will kill me."

Later, after they reached home, Curtis started swearing at Ms Brand and said his ex-wife Marie was "worth ten of her". He then phoned Marie and deliberately revealed he had still been having sex with her after starting his relationship with Ms Brand, it was claimed.

In another incident, Curtis allegedly attacked Ms Brand before kicking her dog into the garden when it bit him while attempting to defend her.

The jury heard that when she threatened to dial 999 he smashed a glass over his head and said: "Call the police. I'll have you arrested for assault."

In August 2006, after other incidents that included him pulling on the handbrake of her car as she drove at 60mph, Ms Brand decided to leave him.

That night she awoke in bed to discover the house full of fumes and found Curtis had turned on a petrol-driven motor in the utility room.

Mr Cranmer-Brown said: "She was terrified. She was extremely frightened about what he would do next. She went to bed shaking like a leaf. He was lying next to her. He pulled the duvet above her mouth and nose.

She was anxious about whether he was going to smother her."

Curtis moved out after the incident but continued to bombard Ms Brand with text messages in which he declared his love for her.

She eventually received one saying he had removed his belongings from the house – but when she returned home she found the property in disarray.

Mr Cranmer-Brown said Curtis had broken her vibrator, emptied every cupboard, left on every light, turned up the heating to 30 degrees, and emptied her freezer destroying £100 worth of frozen food.

Ms Brand told the court a male colleague who accompanied her to the property spotted the "bent and snapped" vibrator when they checked the bedroom.

"I wasn't sure whether I was going to make a formal complaint I was embarrassed. I had only recently bought it."

When later questioned by police Curtis said they split up because they argued so much. But he denied ever assaulting Ms Brand, instead insisting he was sometimes forced to restrain her when she became violent towards him.

Curtis denies charges of harassing Ms Brand, attempting to administer a noxious substance to her and causing a danger to road users. He also denies theft of a digital camera and criminal damage.

• The trial continues.