London's mayor and the leader of the RMT accused each other of holding a gun to the heads of Londoners.
The confrontation came during the Mayor's monthly phone-in show on LBC 97.3 - thought to be only the second time the two men have spoken.
Johnson agreed to take a call from Crow after learning the RMT leader was standing outside City Hall hoping to confront him.
In a brief phone conversation Crow called on the mayor to have a face-to-face meeting. Johnson said he would be happy to sit down if the union called off the strike.
The mayor urged the unions to return to the negotiation table.
What you have got to do is call off this pointless strike which will do nothing but cost your members.
The stalemate suggests little hope of a breakthrough before RMT and TSSA members walk out at 9pm.