A SERIAL sex beast was put behind bars for six years last Friday despite his own defence counsel saying he merited a life sentence.  A court was told 47-year-old Kenneth Sargeant, crept into the room of an 82-year- old woman and assaulted her while visiting his mother in a residential home in Farnham  It also learned that this was just the latest in a string of sex offences - including the rape of a 14-year-old schoolgirl - stretching back more than 25years  The full extent of Sargeant's predatory perversion was laid bare at Guildford Crown Court where he pleaded guilty to assault by penetration but denied a further charge of rape which was left to lie on the file.  Simon Connoly, prosecuting, told the court that his latest victim was terrified he was going to kill her as he repeatedly used the "F" word during the attack.  He said Sargeant, of Park Barn, Guildford, was visiting his mother at the home on April 6 this year when he sneaked off and entered the woman's room, closing the door behind him and saying he loved her before carrying out the sexual assault.  Mr Connoly said: "A member of staff saw that the door was closed and thought it was unusual.  "She knocked and when she went in she saw the defendant kneeling by the woman.  "He got up immediately, but it was obvious his trousers were down and he was pulling them back up.  "She went to get a senior member of staff, and when she returned he was still there on his knees with one hand on her leg."  Sargeant denied doing anything wrong, and left after it was suggested he was doing something inappropriate.  The court heard Sargeant had a a number of convictions for sexual offences dating back to 1980, including four years in jail for raping a 14-year-old girl.  He was also jailed for indecently assaulting a 26-year-old woman in a wood and threatening to kill her.  Simon Molyneux, defending, said that considering Sargeant's history of sexual offending, it may be appropriate to give him a discretionary life sentence in order to protect the public.  He said: "Mr Sargeant pleaded guilty to this offence which is a very important matter in this case.  "Many defendants faced with this type of allegation are completely in denial and will not accept at all that their behaviour was wrong.  "The defendant is unable to address his life- long addiction to alcohol. Once there is an insight into this type of behaviour it is possible to address it."  Sargeant was told by Judge Derek Inman that there was a significant risk of him re- offending and causing serious harm in the future.  Judge Inman said: "You pleaded guilty to assault by penetrating of this old lady. It is of course punishable by life imprisonment, but I do not see it as sufficiently serious to impose a life sentence.  "Thankfully she managed to wriggle free in time, but nevertheless it must have been a terrifying experience for her.  "You have a very large number of previous convictions for various types of rape, and many other serious violent offences.  "You take no responsibility for your offending, attributing it to your alcohol problems. You have a number of psychiatric problems.  "The aggravating factors are the age and vulnerability of the 82-year-old victim, and the degrading acts of sexual behaviour.  "In these circumstances I'm required by law to impose a sentence of imprisonment for public protection.  "After that you will be on licence for the rest of your life, and you will be placed on the sex offenders register."