Conductors have been asking for a pay rise comparable to the 18% increase recently awarded to drivers at the company.

BBC: Arriva strike 'far from over'

Members rejected a 2.45% pay offer and are asking for a rise of 6%, or 50p an hour.

BBC: Oxfordshire council staff strike

In 2011, workers staged a three-month protest asking for better pay, with miners only going back to work after negotiating a close to 40% pay rise.

BBC: Freeport's Grasberg copper mine