Previously there were no set guidelines for judges in these cases, and they could use case law to decide the length and seriousness of any sentence. Last year an inquest found that the 96 Liverpool fans had been unlawfully killed, in part due to the actions of police officers. Judges have the ability to award a life sentence where they feel it is appropriate, for example in situations where the perpetrator is particularly dangerous, a situation which does not tend to arise in gross negligence cases.But average sentences have tended to be much lower than for other manslaughter offences, with the longest sentences given tending to be between six and eight years. According to the most recent figures the average sentence for those convicted of gross negligence manslaughter in 2014 was four years. The Council’s analysis of 16 sentences given during that year found that the shortest was just nine months. The new guidelines give a minimum sentence of one year for the least serious offences. Nazir AfzalCredit:Heathcliff O’Malley Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. Former Chief Superintendent of South Yorkshire Police David DuckenfieldCredit:Phil Noble/REUTERS Judges have been told to issue tougher sentences for gross negligence manslaughter in the wake of the Hillsborough and Grenfell disasters.There have previously been no set sentencing guidelines for the offence but the longest sentences were usually for less than ten years. Now the Sentencing Council has moved to tell judges that they can hand out prison terms of up to 18 years in the most serious cases.The new sentencing rules for gross negligence manslaughter published today propose that “cost-cutting” offenders who have a “serious disregard” for the safety of others should receive more severe penalties.Previously judges had to act based on previous case law, and there were concerns that this meant that the worst offenders were not being given enough prison time. Under the new guidelines offenders will be sentenced more harshly where they were motivated by financial gain, when they knew that their actions were likely to cause harm or if they were in a “dominant role”, if they had acted alongside others. If convicted, perpetrators of historic offences would be judged under the new criteria. Last week it was announced that David Duckenfield, the South Yorkshire police officer who was in charge of policing at Hillsborough stadium when 96 people were killed in a crush in 1989, would be charged with gross negligence manslaughter for his part in the tragedy. The average sentence for those convicted of manslaughter on the grounds of diminished responsibility was 10 years, and the longest was 20 years. Manslaughter sentences were examined after Chris Grayling, the former Justice Secretary and Lord Chancellor, said in 2014 that sentences for “one-punch” manslaughter cases should be reviewed amid concerns that they were too lenient. Analysis carried out by the Telegraph in 2014 found that the average prison term for reported cases of one punch manslaughter since 2010 was three years and ten months. Keir Starmer, the former Director of Public Prosecutions, revealed last month that manslaughter charges were being considered over the Grenfell Tower disaster, in which at least 80 people died.His disclosure followed comments by Nazir Afzal, a former chief crown prosecutor, who told the Guardian that those responsible for the management and maintenance of the building could be held responsible. He said: “All have a duty of care. If they have been grossly negligent and that led to a loss of life, then it can be argued that they have committed manslaughter.”Gross negligence manslaughter is used to prosecute people who fail in a duty of care, causing someone’s death. It includes parents or carers who do not protect their ward from a clear danger, employers who fail to look after the safety of their workers or doctors who fail to care properly for a patient. The Sentencing Council said: “In considering the factors that make an offence of gross negligence manslaughter more or less serious the Council came to the conclusion that it would be appropriate for sentences to increase in some situations.”Typically these are cases where an employer has had a long standing, utter disregard for the safety of employees and is motivated by cost cutting.” A consultation period will run until October with the new rules due to be introduced from the middle of next year. Last year restaurant owner Mohammed Zaman was jailed for six years after causing the death of customer Paul Wilson, 38, who was allergic to peanuts. Zaman had switched almond powder for a ground nut mix, Teesside Crown Court heard. A separate offence of corporate manslaughter exists for companies which cause deaths because of severe management failings. These can be punished with an unlimited fine.