Angry commuters were subject to delays of up to an hour on the hottest day of the year after the heatwave melted overhead power cables.

Monday’s delays, which left thousands waiting in temperatures over 30C (86F) for trains to Ilford, Seven Kings and Goodmayes, were caused the heat causing 1940s-era cables to sag and speed limits were introduced across the National Express East Anglia routes.

There were futher delays for passengers on Tuesday morning as engineers worked to repair the problem.

Chadwell councillor Wes Streeting was forced to travel from Redbridge Town Hall via Gants Hill tube station to get to Liverpool Street, a 45 minute trip instead of what should be a 20 minute direct route.

He said: “National Express East Anglia have been running a shambolic service for some time. When delays do occur, which is quite frequently, their customer service is appalling. It is outrageous that commuters are being asked to pay more each year for a worsening service.”

A spokesman for National Express East Anglia said: “Due to high temperature on Monday 27 June, speed restrictions have been imposed due to the design of the overhead line equipment.

“This equipment is subject to major renewal which will prevent the need for speed restrictions in the long term.”

Network Rail, who are responsible for maintaining the cables, said speed limits of up to 60mph had to be introduced on Monday.