The mother of a teenage ground worker killed in a farm machine in Bristol has branded the £7,500 fine handed to his bosses as "disgusting".

Father and son Roy and Michael Hill were convicted on health and safety breaches following the death of 17-year-old Lee Mason, of Lisburn Road, Knowle West in April 2007.

Bristol Crown Court heard Lee was working on a farm at RE Hill and Son in Dundry when he became snagged by a roller of a diesel powered soil sifter and was pulled towards it, crushing his neck.

Business owner Roy Hill, 66, and manager Michael Hill, 32, were cleared of manslaughter by gross negligence but found guilty of failing to provide the youngster with proper training and supervision.

On Friday The Honourable Mr Justice Jack was told RE Hill and Son had sustained substantial losses due to hard times and Roy Hill was drawing £30,000 a year from the business while his son was taking a modest £17,000.

The Judge fined Roy Hill £5,000 and Michael Hill £2,500 and he ordered Roy Hill to pay £1,500 prosecution costs and his son costs of £500.

The judge told the court Lee had become trapped when he was working alone after someone unknown had removed a vital safety guard.

He told the court: "There was not a sufficient emphasis on safety in the running of the business.

"The system was lacking and checks were not made.

"Neither of you wishes any harm to Lee Mason.

"You both wished to help a young man with disadvantages to get a start in life and you and your family have been devastated and that has to be your real punishment."

Lee's mother, 41-year-old Jenny Mason, told the Bristol Post: "I am disgusted and I think the health and safety people have been treated disgustingly.

"I thought it would be a bigger fine to deter other people.

"Now people will think it doesn't matter if you haven't got a safety guard on your machine because you won't get done for it.

"RE Hill and Son is an established business and we as a family believe that when Lee left for work he would be working in a safe environment.

"It is now clear that health and safety was non-existent and we were unaware of this.

"Nothing can bring Lee back but we hope that he did not die in vain.

"We urge all employers, employees, schools and parents to be made aware of the health and safety risks involved with employment because even if one life is saved some good has come of Lee's death."

Lee's natural father, Michael Fennell, 42, an HGV driver from Daventry Road in Knowle, told the Bristol Post: "No amount of money can put a price on anybody's child but I am disgusted with these fines. I am gobsmacked."

Philip Mott QC, prosecuting, told the court it was exactly 13 years ago when Roy Hill was jailed for three months after pleading guilty to breaching health and safety regulations regarding demolition work he undertook in Bristol involving the removal of asbestos in which there was no protection put in place for workers at the site.

For that conviction he was ordered to pay £4,000 costs.

Peter Blair QC, defending Roy Hill, said RE Hill and Son made substantial losses in 2008.

He said: "The business has already experienced the consequences of recession and there's a need to cut their charging rate in order to be competitive."

Mr Blair said his client would give precedence to paying any fine over developing the business and, ironically, one of the easiest machines to sell would be the soil sifter on which Lee died.

Paul Garlick QC, defending Michael Hill, stressed his client had shown genuine remorse and accepted the fact Lee was working by himself without a guard on the machine.

He said: "There is no evidence Michael Hill knew the machine was being operated with the guard off and his failure is of failing to ensure his employees did not operate the machine with the guard off."

Mr Garlick said his client had some £200 in the bank, was married with a small child and though he lived rent free he had taken out a £25,000 loan to refurbish his cottage.

Lee's mum Mrs Mason said she didn't know why there was no mention of other assets belonging to Roy Hill.

She said: "We believe he's got a Rolls Royce in his garage and loads of trucks which he takes to shows at fairs in the summer.

"His wife even has a brand new car which they got a couple of weeks after Lee died."