LONDON (AP) — A British union has called for a 24-hour strike of Uber drivers in London, Birmingham and Nottingham, putting up a “digital picket line” to demand better pay and conditions.

The Independent Workers Union of Great Britain, the IWGB, is asking the public to support drivers “by not crossing the digital picket line by not using the app during strike time.” The strike begins Tuesday, and it was not clear how many drivers would join in.

Union official James Farrar says “after years of watching take home pay plummet and with management bullying of workers on the rise, workers have been left with no choice but to take strike action.”

The union wants Uber to accept employment panel decisions that classify drivers as workers, not independent contractors. Uber is appealing.