RMT union staff on the London Underground are set to strike on six days across March, April and May, following a majority of RMT union members' support of action. The first walk-outs will begin on March 24 and will take place across the remaining 24 hours. The strikes are due to the introduction of a compressed four-day working week for tube drivers, raising concerns about shift lengths, working time arrangements and the potential impact on fatigue and safety. The RMT has threatened to take action if London Underground does not resolve these issues. The length of the strikes, which will last three months, could end sooner if an agreement is reached between the RMT and TfL.