Ministers must set out how they will accommodate any “substantial” increase in prisoners as a result of proposed new sentencing guidelines for knife offences, MPs say.
Draft guidance for courts dealing with a number of crimes involving knives and other weapons was published by the Sentencing Council last year.
The proposals aim to ensure judges and magistrates have guidelines that are up to date and take into account changes to laws since the last set were produced in 2008.
A report from the Commons Justice Committee said the council expected the new guidelines for adults to increase the proportion of offences that resulted in a custodial sentence, but it has “been unable to estimate with any certainty how sentencers’ behaviour may change”.
It suggested that, were all such offences to lead to imprisonment, it would result in about 1,800 additional offenders receiving a custodial sentence of about two months, with a net cost of about £2.7 million.
However, the council considers it “very unlikely” that all offenders will receive custodial sentences under the new guidelines and believes the figure will be lower.
Tory MP Bob Neill, chairman of the committee, said: “We appreciate how difficult it is for the Sentencing Council to predict the impact of new guidelines but we are concerned about the prospect of a substantial increase in the number of custodial sentences if the draft guidelines are introduced in their present form without a better understanding of their impact.
“We think that the Ministry of Justice should be asked to clarify how any increase in the prison population would be accommodated.”
The proposed guidelines do not cover crimes where a knife or other weapon is used to harm someone, nor the use or possession of firearms.
Responses to the consultation will be examined by the council before it publishes the final version.
A Ministry of Justice spokeswoman said: “We are clear that those who carry knives should feel the full force of the law.
“These new guidelines will help ensure sentences reflect the devastation caused to families and communities.”