Union leaders said up to 5,000 tests could be cancelled because of the 48-hour stoppage, which continues tomorrow, by administration workers in the Driving Standards Agency (DSA). The Public and Commercial Services union (PCS) which represents civil service workers, timed the action to coincide with the second half of a 48-hour walkout by thousands of staff in the Department for Works and Pensions (DWP) in a separate row over pay.