Lord Phillips said more work would be done on domestic violence

The Sentencing Guidelines Council said non-custodial sentences should be applied only in exceptional cases.

The council's Manslaughter by Reason of Provocation guideline says discovery of infidelity should not be accepted as a high degree of provocation by courts.

"Provocation" can be used to reduce an offence of murder to manslaughter.

Lord Chief Justice Lord Phillips, the chairman of the council, said details of individual cases varied considerably, making it "extremely difficult" to be prescriptive.

We have felt that in the past, some sentences for manslaughter by reason of provocation have been a little low Ken MacDonald QC Director of Public Prosecutions

"In the guideline, we have had to strike a difficult balance between recognising the sanctity of human life, whilst giving effect to legislation that recognises human fallibility under provocation," he said.

"The guideline covers all manslaughter offences where provocation is involved, not just killings that occur in a domestic context."

Lord Phillips said additional work would be carried out on the issue of domestic violence in 2006.

Domestic abuse

Director of Public Prosecutions Ken MacDonald QC, who sits on the council, said: "We have felt that, in the past, some sentences for manslaughter by reason of provocation have been a little low.

"It's not a situation which relates purely to women - it relates to men as well," he added.

Mr MacDonald said the new framework also acknowledged that high levels of provocation can build up over time, where individuals were subjected to domestic abuse over many years.

The council released a draft of the Manslaughter by Reason of Provocation guideline in May 2005, which was then subject to consultation.

The final guidelines will apply to anyone sentenced for the offence after 28 November 2005.

Levels of provocation

The guidelines state that the key factor that will be relevant in every case is the nature and the duration of the provocation.

There are three sentencing ranges defined by the degree of provocation - low, substantial and high.

The guidelines advise starting-point sentences, which may then be reduced or increased within the sentencing range - once mitigating and aggravating factors are taken into account.

An aggravating factor could be concealment of a crime, while a mitigating factor could be that the victim presented an ongoing danger to the offender or others.

Where the level of provocation has been deemed low, the sentencing range is from 10 years to life, with a starting point of 12 years.

The guidelines give a starting point of eight years for substantial provocation with a range of four to nine years.

In cases where the level of provocation is deemed to have been high, the guidelines state "if custody is necessary" the sentencing range should be up to four years, with three years as a starting point.