The alarm was raised by alert workers at Durkan’s Kingsland Wharves job on Hertford Road in Hackney.

The emergency services said 20 firefighters were involved in a rescue operation after being called to reports of a man collapsing in the cab of a 100ft crane.

Firefighters used the crane’s access ladders to reach the driver and give him first aid.

The crews then used rope lines and other specialist rescue equipment to move the driver from one crane to another one next to it and lower him down to the ground.

The man was treated by London’s Air Ambulance and was taken to hospital by London Ambulance Service.

Durkan Construction Director, Mike Nelson, said: “At 9.10am our Crane Supervisor, Colin Kavanagh, was alerted to a concern about the crane driver, Keith Lewis, who was suffering with severe chest and stomach pains.

“When Colin climbed the crane mast with another driver and the Slinger Signaller to investigate, they found Keith collapsed on the floor of the cab.

“Emergency Services were contacted immediately and dispatched a Rapid Response team including a London Air Ambulance helicopter; quickly followed by fire and rescue vehicles.  A crane from a nearby site was deployed to assist a rescue and Keith was lowered to the ground and treated by 9.45am.”

Ian Cresswell, Health & Safety Director said: “We had an incident that needed dealing with quickly and carefully.

“Our team did a great job and we are also grateful to Allenbuild who provided the second crane.  We especially want to thank the Emergency Services and their Rapid Response Team for the incredible job they do”.