The number of people arrested for possessing cannabis has fallen by more than one third since the drugs laws were relaxed.
But the Home Office said the down-grading of cannabis, from a class-B to class-C drug exactly one year ago had made no difference to levels of use. There were an estimated 43,750 arrests over the past year, compared with 68,625 in the previous 12 months.
Ministers calculated the fall had saved about 200,000 hours of police time, freeing them to tackle the use of class-A drugs such as heroin and crack.
Following reclassification, cannabis is now ranked alongside anabolic steroids and some prescription anti-depressants. Although its possession is still a criminal offence, offenders are not usually arrested.
According to details of the British Crime Survey which were published by the Home Office yesterday, 10.8 per cent of adults report taking cannabis over the past year, compared with 10.9 per cent in the previous 12 months.
It also discovered that the proportion of 16- to 24-year-olds using the drug had fallen from 28.2 per cent to 24.8 per cent over the past five years.
Caroline Flint, a Home Office Minister, said: "The picture is encouraging, with significant savings in police time which can now be used to drive more serious drugs off our streets and make our communities safer."
Because each arrest takes an average of eight hours to process, the 24,875 fewer arrests saved 199,000 hours of police time. She added: "I'm pleased figures show that some predictions that cannabis use by young people would increase were wholly unfounded."
Martin Barnes, the chief executive of the charity DrugScope, said: "We supported, and continue to support, the reclassification of cannabis.
"It is encouraging that cannabis use among young people has been declining, although it is too soon to draw conclusions from the latest figures on the impact of reclassification.
"The reclassification of cannabis was in recognition that all drugs are not the same."
But the Tories, who have pledged to reverse the reclassification, accused the Government of releasing misleading statistics. They pointed to a separate survey that suggested overall drug use by teenagers has doubled since 1997.
David Davis, the shadow Home Secretary, said: "Downgrading cannabis was a mistake, which has sent mixed messages to the young and the vulnerable about the dangers of drugs. Mr Blair's government is deceiving itself by using misleading figures to measure cannabis use."Reuse content