Federal legislation limiting the amount of credit prisoners can get for time spent in custody before and during their trial received royal assent Friday.

Up to now, it has been common practice among judges to reduce prison sentences by two days for each day a person spent in jail while awaiting trial and sentencing. In rare cases, the ratio was 3-to-1 if their detention conditions were deemed particularly difficult.

The new legislation provides that as a general rule, the amount of credit for time served will be capped at a ratio of 1-to-1.

It will permit judges to give credit at a maximum ratio of 1.5-to-1 only when circumstances justify it, and they will be required to explain what those circumstances are.

No change in the 1-to-1 ratio will be allowed under any circumstances for people who have violated bail conditions or who have been denied bail because of their criminal record.

The legislation "better reflects truth in sentencing and gives Canadians greater confidence that justice is being served," Justice Minister Rob Nicholson said in a release.

Enhanced credit for time spent in pre-sentencing custody became a common practice to compensate for conditions such as overcrowded detention facilities, the lack of programs or activities for inmates and the fact that the time did not count toward their eventual eligibility for parole or statutory release.

However, the Justice Ministry said the generous 2-to-1 ratio is partly responsible for an ever-increasing number of accused being remanded without bail, to the point where the number of people now in pre-sentencing custody exceeds the number of prisoners actually serving sentences.

The ministry said federal, provincial and territorial working groups that looked at the issue determined that limiting credit for time served before sentencing was one way to reduce the size of remand populations.