A man killed his girlfriend during an outdoor sex session after drinking 45 pints of beer has had his sentence slashed on appeal.

Lee Portwine, 41, of Pound Hill Parade, Crawley, admitted murdering Una Whitney by stuffing mud in her mouth and headbutting her after they went to have sex in woods.

The couple, had consumed large amounts of alcohol and drugs when they left a friend's wedding reception on July 26 2003.

They walked into woods near the Gatwick Worth Hotel, near Crawley, but a fierce argument broke out.

Portwine, who lived with Whitney in Crawley, admitted murder and was jailed for life - with a 16-year minimum term - at Lewes Crown Court on March 29 2004.

Today the minimum term was cut to 12 years by top judges at London's Criminal Appeal Court after the court heard Portwine argue that the sentencing judge had unfairly counted the sexual behaviour as an aggravating feature.

Lord Justice Scott Baker, sitting with Mr Justice Mitting and Judge John Diehl QC, told the court Portwine had been drinking since the day before the reception, consuming a total of 45 pints plus a mixture of drugs over the two days.

His lover, with whom he had a violent relationship, was also very drunk said the judge, when Portwine persuaded her to go outside to the woods surrounding the hotel to have sex.

They then indulged in "perverted behaviour", including Portwine shoving handfuls of mud and twigs into his girlfriend's vagina and mouth, choking her, and squeezing her throat during sex.

This activity, while "degrading", was consensual, the judge said today.

But when the girl began to feel uncomfortable and started to shout angrily at Portwine he headbutted her, breaking her nose and cheekbone and knocking her unconscious.

This blow, plus the mud and twigs clogging her windpipe, led to her death.

Portwine was arrested the next day after confessing to friends and family and giving himself up the police Tattooed and weeping in the dock as the judge described the murder, Portwine heard the court agree yesterday that his his minimum jail tariff had been too long and that the sexual activity, though distasteful, should not have been allowed to colour the sentence.

Lord Justice Baker said: "The fact that the victim and the offender indulged in perverted behaviour is not an aggravating feature, although it was degrading.

"There are a number of mitigating features, including lack of intention to kill and real remorse.

"This was a particularly unpleasant killing committed by a man with a number of previous convictions, but the correct minimum term was 12 years," the judge concluded.

Paul Lewis, QC, prosecuting, said Portwine had pushed earth into the care assistant's mouth and then headbutted her because he was embarrassed someone might hear them arguing.

They argued when Ms Whitney began shouting that he was hurting her during sex.

Mr Lewis said Portwine later told police: "We were into the asphyxiation thing where you get a buzz when you can't breathe."

Portwine told police he and Ms Whitney had taken Ecstasy during the evening. Tests showed Ms Whitney had enough alcohol in her blood to make her three times over the drinkdriving limit. They also showed a single headbutt would only account for some of the injuries and that Ms Whitney had been hit more than once.

The tests showed she had probably choked to death on the mud while unconscious, Mr Lewis said. A bite mark was also discovered on Ms Whitney's left cheek. Mr Lewis said the couple had a stormy relationship.

He said: "The relationship appears to have been violent. "The deceased was frequently seen with black eyes which she told friends he had caused.

"It appears the defendant was a possessive man and did not want the deceased to have close friends.

"Sometimes he would lock her in the house."

After the attack Mr Lewis headed back into the hotel. He told the bride, who was still drinking in the bar: "I headbutted her and I split her head open. I can't wake her up."

Portwine handed himself into police the following morning. Sentencing Portwine to life in prison, Mrs Justice Rafferty said: "It is clear that in late July 2003 drugs and alcohol raised their ugly head in miserable circumstances leading to the death of Ms Whitney.

"The relationship had turbulent aspects. If only that was all her loved ones had to bear."

The judge said the minimum sentence tariff would be decided after probation service reports.