A forensics lab has stopped analysing samples taken from drink-drive suspects by police forces in England and Wales.
The Forensic Science Service (FSS) had planned to close the lab in Lancashire and move the work to south London.
The closure will go ahead next month but there will now be no move as the government has said the FSS would be wound down by next year.
Forces have been told to refrigerate blood and urine samples until another forensic service provider can be found.
However this would have "no impact on the criminal justice process", according to senior officers.
The FSS confirmed it would not be doing any more tests on drink-drive samples but it is understood there are at least four other providers who already do similar work.
A memo from the National Policing Improvement Agency (NPIA) to chief constables said the FSS said would no longer process any samples taken under the Road Traffic Act.
Officials hoped to to find "alternative suppliers" within seven working days, it added.
The memo stated: "We appreciate the challenges and difficulties that this change may cause your force. However, we would ask that you continue to work with us whilst we resolve this issue."
The move affects cases where the suspect is unable to provide a breath test or the equipment is faulty, or opts for an alternative means of testing.
The government announced in December that the Birmingham-based FSS was to close.
The move, called Operation Slingshot, is being overseen by Wiltshire Deputy Chief Constable David Ainsworth, working with the the Association of Chief Police Officers (Acpo), the Home Office and the NPIA.
A joint statement from Acpo and the NPIA said: "As part of the managed wind-down of the Forensic Science Service a number of services currently delivered to police forces will be discontinued.
"There is capacity to undertake these services by other forensic suppliers under the NPIA's national framework for the supply of forensic services to policing.
"A transition plan was already in place for the transfer of the testing work undertaken by the Forensic Science Service. Swift arrangements will now be made to ensure that alternative suppliers provide the analysis for Road Traffic Act drink and drug cases. There are already other forensic suppliers who undertake this work.
"A small number of samples may be held by police forces whilst the new arrangements are put in place quickly, but this will have no impact on the criminal justice process."
The FSS, which employs 1,600 people, carried out the testing at a lab in Chorley and had planned to move operations to its site in Lambeth in south London.