The dispute at Grangemouth has led to renewed divisions within the Labour Party.
Labour MPs have told The Scotsman they believe Scottish leader Johann Lamont is “not in control” of the party after senior figures at Holyrood openly came out in support of yesterday’s Unite strike.
Drew Smith MSP, the shadow justice secretary, was on the picket line at Grangemouth, along with senior Edinburgh Labour councillor Cammy Day.
Shadow health secretary Neil Findlay also tweeted his support.
The row stems from the Falkirk selection debacle to replace Eric Joyce, which was marred by allegations that Unite was trying to fix the result, though later cleared. Stephen Deans, a Grangemouth union official, was one of those alleged to be behind fixing selection as constituency chairman.
One Scots MP said: “Why is she [Johann] allowing her frontbench to support Deans? She knows exactly what he got up to in Falkirk.”
Another MP said: “Lamont has lost control of her front bench and is not willing to hold a sensible line. I imagine Ed Miliband will not be best pleased, given that as a rule at Westminster we don’t support strikes.”
But Ms Lamont has called for both sides in the negotions to come to an agreement, adding: “This is not the way we should be engaging in workplace disputes in the 21st century.”