Striking London Underground workers and their trade union allies have condemned the Labour Mayor of London claims of bad faith on their part.
Rail union RMT hit back on Friday evening at Mayor Sadiq Khan's tweet that morning calling the strike "unnecessary" and accusing them of refusing to negotiate.
RMT members are on strike over new working arrangements drivers on overnight shifts that Transport for London (TfL), whose board Khan appoints and chairs, wants to introduce.
The union says the new arrangement will see previously-dedicated 'Night Tube' drivers moved between day and night shifts at managers' convenience. It argues that will increase fatigue and jeopardise passenger safety.
In an letter to Khan, included in its statement on his comments, RMT General Secretary Mick Lynch pointed out the union had offered to go to conciliation service ACAS with TfL.
"You should know that our reps and members have seen the email in which RMT offers to meet at ACAS," Lynch wrote, stressing that they were "justifiably furious at the complete misrepresentation of our position in the public domain."
The union leader also said the strike was "rock solid" across the network.
"The tube strike action this morning is rock solid in all depots," Lynch said. "The widespread impact on services is solely down to the management failure to recognise and address the anger of their staff at the imposition of damaging and unacceptable working practices."
"This action was wholly avoidable if LU bosses hadn't attempted to bulldoze through arrangements that abolished the Night Tube driver grade, lumping everyone into a central pool where they can be shunted about at will in a drive to cut costs," he added.
Officials from fraternal trade unions condemned Khan's attack on the RMT.
And left-wing journalists also weighed in on the union's side.