Representatives of both sides in the stalls handlers' dispute will meet in Newmarket today in an 11th-hour bid to avert industrial action at Royal Ascot next week.
Officials from the Transport and General Workers' Union and stalls handers' employers RaceTech met in Newmarket on Wednesday, but failed to reach a settlement in the dispute over allowances.
Strike action planned means three races at four of today's and four of tomorrow's Flat meetings, and all races from Monday - apart from at Brighton - will begin with a flip start.
This will affect the Royal meeting, which begins on Tuesday.