The former most senior criminal judge in England and Wales has said the government has to recognise “locking people up for longer” does not deter crime.
Sir Brian Leveson, the former head of criminal justice, told an online event that detecting crime was a better way of reducing offending than long prison sentences.
The retired judge also said “more social care needs to be devoted” to offenders or those at risk of committing crime.
He spoke as the Ministry of Justice plans a review of sentencing, as promised by Labour in its general election manifesto.
The length of sentences has come into focus as prisons across the country struggle with an overcrowding crisis.
The prison population in England and Wales has hit a record high, forcing the government to explore options to make more cells available in jails.
The Labour government said a scheme to release some offenders early – which started this month – was necessary to prevent the prison system from running out of space.
Meanwhile, five former senior judges – including Sir Brian – signed a paper that called on the government to reverse the trend of imposing ever-longer sentences.
The paper argues there is little evidence that longer prison terms have contributed to falling crime rates.
The judges say changes to the law over decades have driven up sentence lengths, and point out the UK’s prison population has risen from about 40,000 in 1991 to more than 88,000 today.
Sentencing review
Sir Brian spoke about the issue of “sentence inflation” at an online event organised by Howard League, a penal reform charity.
When the panel was asked what they would like to see in the government’s review of sentencing, Sir Brian said: “There has to be a recognition that deterrence is not achieved simply by locking people up for longer.
“Deterrence is achieved by detecting crime, not by the sentence that necessarily follows for those who are convicted of crime.”
He went on to say “there are people who need to be locked up for a very long time, who are very dangerous”.
“But you only have to look at the mental health and drug problems of those in prison, the literacy and numeracy of those in prison, to realise that a lot more social care needs to be devoted to those, not merely who do commit crime, but to those who are at risk of committing crime, to keep them away from criminal justice issues.”
In a Q&A session, the panel were asked if there was a link between the political culture of campaigning for stiffer sentences for certain crimes and the overcrowding crisis in prisons.
Nicola Padfield KC, a barrister and professor of criminal and penal justice at the University of Cambridge, said: “Of course we owe the victims of dreadful crimes, the families of murdered people, enormous public sympathy.
“We don’t treat victims very well in our system. But you shouldn’t form sentencing policy on the basis of the rare, dreadful crimes.”
Sir Brian agreed, saying “anybody who has lost a member of their family to murder, or who has been the subject of serious crime, inevitably feels let down if the justice system does not pass a sentence which they consider commensurate to the enormous loss they’ve felt”.
But he added “that can’t drive all of our policies, because if it does, you get the result we’re getting”.
Andrea Coomber KC, the chief executive of the Howard League, said the Sentence Inflation paper had credibility.
She said: “The response so far from ministers has been they will take it into account. They welcomed it.
“And we’re in the process of organising a meeting with the judges and the minister.”
The BBC has asked the Ministry of Justice if it wishes to comment.
The reform of sentencing has been controversial and faced political opposition when governments have attempted it in the past.
Former immigration minister Robert Jenrick has been taking a tough-on-crime line as he vies with four other candidates to be the next Conservative leader.
In a post last month, Jenrick argued that “prison works”.
He wrote: “We need more prisons so we can jail repeat offenders for longer and cut crime.
“We believe in rehabilitation and second chances, but we can’t be taken for fools.”