The plans have sparked controversy not least because Mr Clarke said in an interview that some rapes were more “serious” than others.
Mr Clarke prompted calls from the Opposition for him to resign, while defending the Government proposals to halve the sentences of some rapists if they made early guilty pleas.
He angrily rejected reports that sex attackers could face just 15 months behind bars as a result, insisting “classic” rapes involving violence and unwilling women resulted in longer sentences.
Less clear-cut “date rapes” and consensual sex between teens, one of whom was under age, skewed average sentencing figures, he insisted.
He was later forced to make a public declaration that he regarded “all rape as a serious crime”.
MoJ: £130m budget shortfall
If the Secretary of State has to rethink his plans he will also need to look again at how the Ministry of Justice can plug a funding gap of £130m.
The sentencing plans were seen as a way to cut the department’s £4bn budget as well as easing pressure on the prison population.
In a parliamentary debate last month, Mr Clarke insisted that his plans would make “an enormous difference to costs, police time and the involvement of unnecessary preparations for trial”.
The department has already cut legal aid in a bid to balance its books.
Meanwhile, a new report is critical of another of Mr Clarke’s reforms. The deterrent effect of short-term sentences is lost on criminals who are jailed time and time again according to the Howard League for Penal Reform and the Prison Governors’ Association.
Mr Clarke wants to keep prison for the most serious offenders and cut the number of jail terms under 12 months as part of a “rehabilitation revolution” which would result in thousands of offenders avoiding jail.