A Samaritans volunteer fell asleep as she drove home from an all-night shift, causing a smash which left a woman fighting for her life.

Pamela Evans, 63, had missed a night's sleep to man the helpline's phones and was on her way home from the organisation's Brighton branch when her car veered across the road.

She smashed head-on into a Ford Fiesta driven by Victoria Holt, 25, who was left with a broken neck, a broken leg and a foot so badly shattered it almost needed amputation.

Miss Holt spent weeks in hospital and was forced to cancel her wedding. A pin was inserted from her hip to her knee and she has been left with a permanent limp.

The crash had been caused by a momentary lapse of concentration by Evans, Mid Sussex Magistrates Court, sitting at Haywards Heath, heard yesterday.

She had not been due to work that night but had gone in to cover for a volunteer who pulled out at the last minute.

A pale Evans sobbed quietly as Miss Holt's injuries were outlined to the court.

She admitted careless driving and was fined £300. The maximum penalty is £2,500.

The former doctor's receptionist was allowed to keep her driving licence after the court heard losing it would force her to give up her "good deeds" as a Samaritans volunteer.

The magistrates told her they sympathised with her but said no one should drive while tired.

Outside court, Evans spoke of her devastation and the guilt she feels, saying: "All I can do is apologise and say how sorry I am, although that seems so inadequate.

"The hardest part is living with the fact I've caused Vicky to be so badly injured. Somehow I've got to live with what I did."

Miss Holt had left her home in Haywards Heath to drive to work in Brighton on the morning of the accident last September.

Her fiance and three-year-old son were following in the car behind.

As she drove along Common Lane towards Ditchling, Evans' car suddenly veered into her path and smashed head on into her Fiesta.

Two separate witnesses described seeing Evans' car "drifting" across the road. Both believed she had either passed out or fallen asleep. Neither felt she had pulled out deliberately to overtake. Police concluded neither car was speeding at the time.

Richard Lynn, prosecuting, said: "Miss Holt was later able to give a description and said she was in no doubt it was an overtaking manoeuvre. But certainly the bulk of witnesses describe it as a drifting motion from one side of the road to another."

The court heard Evans, of Kings Ride, Burgess Hill, had thrown herself into her work with the Samaritans after retiring in 2002. She has worked as a helpline volunteer for 18 years.

Tony Hamnett, defending, said: "She wanted to continue to help in the community. In fact she is now a director of the Brighton branch."

He said Evans worked about 12 hours as a volunteer each month and did about nine night shifts a year, although as a director she was in effect on call 24 hours a day.

He told the court: "On night shifts she normally sleeps during the day to ensure she is fit to cope. But this time she received a phone call late in the evening because the volunteer who was supposed to do the shift couldn't make it.

"She had a choice. Either the Brighton helpline would have to close down and there would be no one available to help people in need or she would have to stand in. She stood in.

"It was a busy night, a particularly heavy shift, and she was not able to get any sleep during the night due to the number of calls the centre received."

Evans was not sure what had happened but it was possible she had gone into "micro-sleep" for a moment, falling asleep even though her eyes were open.

Mr Hamnett said: "This was a momentary lapse and, though the consequences and injuries to Miss Holt are terrible, you must sentence on the degree of carelessness.

"This is a tragedy for everyone. It has devastated two lives, Miss Holt's and Mrs Evans'.

"She is a lady who does good deeds for our community and she has never appeared in court before.

"She has assisted the police and pleaded guilty at the first opportunity.

"If you disqualify her, what the community will be losing is a qualified director of the Samaritans, someone who this community needs.

"Nothing can put the clock back, nothing can reverse the injuries Miss Holt received."

Evans, who was in hospital for ten days after the accident and suffered two broken vertebrae in her back, was accompanied to court by her husband of 34 years.

She was ordered to pay £55 costs and given nine points on her licence.

Miss Holt was not in court but said: "I do feel a bit sorry for this woman because I know it was an accident."