The shortest jail terms should be scrapped and replaced by tougher probation courses, according to Tory MP Iain Duncan Smith. The former Conservative leader will say that terms of two months or less are "farcical" and do nothing to help thousands of serial offenders. His comments will come in a speech at the publication of a report on the criminal justice system by his Centre for Social Justice think tank. It calls for an end to sentences of two months or less and the introduction of more closely monitored community sentences with a stronger focus on rehabilitation and treatment for addicts. Under the proposals, the courts would be given the power to quickly haul offenders into prison if they breach their probation terms. They also involve a more active role for the probation service and better provision of drug and alcohol rehabilitation courses. In his speech tomorrow, Mr Duncan Smith will warn that a "revolving door" of serial offenders is "clogging up the prison estate".