Rock solid tube action sends out clearest possible message that issues must now be addressed.

RMT General Secretary Mick Cash said;

"The action is absolutely solid on London Underground ‎across all unions, all grades and all lines and depots. That sends out the clearest possible message to Boris Johnson and his tube bosses that they must now take the staff grievances seriously and get back into genuine and meaningful talks.

"Our dispute is not with the travelling public it is with those who have botched the introduction of Night Tube and who are trying to plug staffing gaps by wrecking any chance of a decent work/life balance for our members. It really is as simple as that.

"The anger and determination of a wholly united tube workforce can be seen on the joint picket lines across the network this morning. Those voices must be heard and understood now and talks convened so that the fundamental issues at the heart of this dispute can be resolved. "