A 52-year-old man who spent hours looking at appalling internet sex abuse sites spiked a young woman's drink with a date rape drug.

The unsuspecting 24-year-old only realised what was happening when another pub customer alerted a bouncer who in turn spoke to the victim.

She was "incredulous" when told that Philip Jones had been seen putting something in her fourth half of lager, saying, "You're having a laugh".

The doorman then spoke to Jones and knocked over the suspect drink, pretending it was an accident, said Michael Stephenson, prosecuting on Monday.

He again spoke to the woman and when she went back into the bar "she looked at her drink and could see there was powder in the bottom of it. She took a sip and then said she was very thirsty and had an upset stomach and wanted a soft drink and declined to drink any more."

She left the premises, The Tap at Charing Cross, BIrkenhead, and when she got home told her partner what had happened.

The next day - February 17 last year - they went to the pub and watched the CCTV footage and it showed Jones putting powder into her glass at 11.40pm.

They told the police and examination of her blood and urine revealed traces of nitrazapam, which is prescribed for insomnia and is in the same family as the date rape drug.

Jones was arrested and he claimed he had put some crushed up pain killers in her drink as she had been complaining of back ache but could not explain why he had done so surreptitiously, said Mr Stephenson.

When his computer was seized and examined indecent child porn images were found, including 69 in a serious category. It was also found that he had been searching internet sites including date rape on 52 occasions and a rape site on 23,500 occasions.

He pleaded guilty to administering a noxious substance for the purpose of facilitating sexual activity and 15 offences involving indecent and extreme pornographic images.

Imposing an eight year extended jail sentence, involving five years behind bars and extended licence for three years Judge David Aubrey, QC said: "It was not only premeditated it was calculated and driven by your perverted sexual desires and intent to commit a sex act upon her.

"The court is quite satisfied what you intended to do with that calculation was to rape her."

He said that prior to going to the pub he had obtained the substance intended to stupefy her and she was extremely lucky that his actions had been spotted.

He imposed an indefinite Sexual Offences Prevention Order and ordered him to sign the Sex Offenders Register for life.

Liverpool Crown Court heard that Jones, a former soldier, of Trafalgar Road, Birkenhead, has previous convictions for a serious sex offence and wounding.

Brett Williamson, defending, said that HGV driver Jones had made frank admissions and recognises he has problems and is "mentally corrupt". He had spared the victim having to give evidence and would benefit from help in prison.