As it entered its fourth chaotic day on Wednesday, Eddie Dempsey, the general secretary of the Rail, Maritime and Transport union gave a surprising reason for the strikes.

Tube staff have launched a full walkout this morning in an RMT-led row with Transport for London (TfL) over pay and conditions, plunging the capital into travel chaos.

A tube strike meant London Underground lines were suspended on Monday, 8 September, as members of the Rail, Maritime and Transport (RMT) union launched industrial action over pay…