"GMB members in the ambulance service have been forced to take a stand in order to protect patient care," GMB organiser Lola McEvoy said in a statement.

"They do not take industrial action lightly and it's always a last resort – but things can’t go on like this; something has to give."

The union said it had more than 1,500 paramedics and ambulance workers at the London Ambulance Service and said its members were "angry over the government’s imposed 4% pay award".

The London Ambulance Service joins the union's members from Yorkshire, North East, West and East Midlands, North West and East of England Ambulance Services who are all planning to vote on whether to take industrial action.

The latest announcement follows similar proposed votes across Britain's healthcare system as both junior doctors from the British Medical Association (BMA) and more than 300,000 members of the Royal College of Nursing (RCN) are set to begin voting on strike action.