At the start of pay negotiations, which take place every four years ahead of the expiry of existing contracts in September, the leaders of the big three US carmakers traditionally shake hands in front of the cameras with the leader of the United Auto Workers (UAW) union.
The tradition goes back almost a century: Wayne State University in Detroit, America’s car-making capital, has unearthed photographs dating back to the 1930s showing the UAW leaders of the time shaking hands with a leader from Ford, Chrysler or General Motors.
