Driving tests face disruption today as examiners across Britain stage a strike over jobs and working practices.
The Public and Commercial Services union (PCS) said the 24-hour walkout by 2,000 examiners and administrative staff would "severely disrupt" driving tests.
The Driving Standards Agency urged candidates booked to take a test to turn up as normal.
The union is protesting at plans to close customer service centres in Edinburgh, Birmingham and London and the loss of up to 80 jobs.
PCS official Paul Williams said: "We remain unconvinced that the Driving Standards Agency's agenda is about road safety and believe it is more about increasing income through cutting staff and services in areas which will have a negative impact on the public.
"Whilst we have been willing to talk to DSA they have consistently refused to provide us with all the information of their plans and continue to plough on regardless.
"With the DSA admitting that they have not costed their proposals, it will be the public and our members who will end up footing the bill for their illconceived plans."
General secretary Mark Serwotka added: "Members taking industrial action today are showing that they are not prepared to sit back as the DSA try to push through proposals which will compromise road safety and lead to a deterioration in the service the public receive.
"Management need to step back from the race to cut jobs and start negotiating mean-ingfully over the key issues of concern."
DSA Chief Executive Rosemary Thew said: "Not all the examiners are members of the union and even if they are, we cannot be sure that they will not turn up for work.
"We therefore want candidates to attend so that practical tests can be delivered if examiners are there.
"Theory tests will be taking place as planned.
"If candidates find there is no examiner to take them on test, a new date will automatically be rebooked by DSA and an out-of-pocket expenses form will be sent along with details of the new test."