A picture shows six buses engulfed in flames when fire broke out at a bus depot.

Transport for London is still investigating the cause of a fire that broke out in Potters Bar on Sunday (May 22).

Emergency services received 73 calls to attend the “significant fire” at Potters Bar Bus Garage at around 2.30pm.

Hertfordshire Fire and Rescue says the first fire engine was on the scene within four minutes.

Andy Hopcraft, the deputy chief fire officer, said: "The first fire engine was on the scene within four minutes. Four buses were well alight.

"Neighbouring properties were quickly evacuated and the surrounding buildings and other buses were protected from fire.

"At the height of the fire, eight engines were in attendance, and a total of six buses were on fire - two electric-hybrid, and four diesel-powered.

"Thanks to the efforts of the firefighters involved, the fire was contained to six buses and did not spread to cause further damage to other buildings or vehicles."

Since then, around 90 London buses were removed from service because of the fire or because they were manufactured by electric vehicle maker Switch Mobility.

A TfL spokesperson said: “We are currently investigating what caused a fire at Potters Bar bus  garage with the bus operator Metroline.

"We apologise for any disruption this causes to local bus routes and are working with Metroline to regain full service as soon as possible.”

The routes that were affected by a reduced service on Monday were:

  • 134 North Finchley – Warren Street
  • 231 Enfield Chase – Turnpike Lane
  • 317 Enfield Town – Waltham Cross
  • 263 Highbury Barn – Barnet Hospital
  • 307 Brimsdown Station – Barnet Hospital
  • W8 Chase Farm Hospital – Lee Valley Leisure Complex

READ MORE: TfL Enfield and Barnet buses hit by Potters Bar depot fire

Discussing the service reduction, TfL continued: “As a precaution, Switch Mobility has asked all operators that use its double decker electric buses to temporarily withdraw them from service while it conducts an investigation and carries out safety checks.

“We have arrangements in place to minimise any disruption on the routes where these buses operate. We apologise to any customers who are experiencing disruption to their bus service.”