The Howard League is very open and accountable

Frances Crook Director

The announcement comes amid a row over MPs who have refused to sign a race pledge put forward by the Commission for Racial Equality.

The Howard League has listed five principles it wants candidates to endorse.

They are that:

• imprisonment should be a last resort
• prisons should provide a "positive experience" and a chance of rehabilitation
• greater use should be made of community penalties
• public resources should be concentrated on preventing crime
• the criminal justice system should be based on repairing the damage done by crime.

Details of the manifesto will be published later on Monday.

The league's director Frances Crook told the BBC: "The Howard League is very open and accountable.

"We are pleased to make publicly available the information that we gather as to who supports us and who doesn't."