The number of motorists caught drink-driving over the Christmas period fell by nearly a fifth, figures show.
Pollice warn that the campaign against drink-driving will continue
Although police in England and Wales carried out more breath tests, fewer motorists were found to be over the limit compared to the previous year.
Figures from the Association of Chief Police Officers show 7,800 drivers tested positive, compared with 9,700 drivers caught in the 2006 crackdown.
Police chiefs have described the fall as "encouraging".
The number of people driving under the influence of drugs was also down.
Acpo figures show that there were 153 arrests for drug-driving, compared with 251 the previous year.
Officers carried out more than 155,000 breath tests in December 2007 - 6% more than during the 2006 anti drink-driving campaign.
Nottinghamshire Chief Constable and Acpo head of roads policing Steve Green said: "The fact that we have tested more drivers than during the last campaign yet arrested some 20 per cent fewer is encouraging.
"It indicates that increased enforcement and a hard-hitting campaign may be starting to have an impact."
However, the figures also suggest that older drivers were just as likely to drink-drive compared to their younger counterparts.
There was no significant difference in the failure rate between older drivers and those aged under 25 - who are statistically more likely to be involved in road traffic collisions.
Mr Green said: "Older drivers, who might be expected to take a more mature and considered decision than those younger than them, are evidently not doing so."
Road safety minister Jim Fitzpatrick said he was "delighted" with the results.
He said: "This sends out a powerful message to anyone thinking of drink driving - you are in a dwindling minority and have an increasingly high chance of being caught."