A strike by London Underground drivers, organized by the RMT union, will commence at midday on April 21, 2025, causing significant disruptions in transport across London. Approximately 50% of the tube drivers are members of the RMT and are expected to participate, while a slight majority from the Aslef union will continue working. The strike will occur in two 24-hour phases, with major service reductions expected on Tuesday and Thursday afternoons, and limited services on Wednesday and Friday mornings. Key lines such as the Piccadilly, Waterloo & City, and Circle lines may not operate at all during the strike. Despite these disruptions, alternative transport options like the London Overground and buses will remain available but are expected to be extremely busy. The strike is rooted in ongoing disputes over working conditions, with the RMT opposing a proposed voluntary four-day work week from Transport for London (TfL). The RMT's general secretary, Eddie Dempsey, criticized TfL for failing to negotiate, while Aslef views the four-day week as beneficial. If negotiations fail, further strikes are planned for May and June.