Emergency workers and officials examine a damaged London bus at the scene of an accident. (DANIEL LEAL-OLIVAS/AFP/Getty Images))

The 80-year-old bus driver who killed a seven-year-old boy and his grandmother after he crashed into a supermarket had received two dozen warning letters about his deteriorating standard of driving, a court heard.

Kailash Chander mistook the brake for the accelerator, thereby causing the crash. He had reportedly ignored warnings not to work when he was tired. Between July 2014 and September 2015, Chander had received 24 letters relating to a ‘spy-in-the-cab’ system called Ecodriver which monitored driver performance electronically.

The accident occurred on October 3, 2015 after Chander, a former Leamington Spa mayor, lost control of the Stagecoach bus and ploughed into a Sainsbury’s supermarket in Coventry.

The entire accident was caught on CCTV and it showed Chander losing control of the bus before it crashed into the supermarket.

The crash happened after Chander had worked three consecutive 75-hour weeks.

He has been charged with two counts of causing death by dangerous driving and two counts of causing serious injury by dangerous driving. Chander has been excused from attending a finding-of-facts trial at Birmingham Crown Court as he was found medically unfit.

Explaining the case against Chander, prosecution QC Andrew Thomas said: “The prosecution say that the collision was caused by a gross driver error.

“It appears that Mr Chander had not appreciated he had left the bus in ‘drive’ – that is, in gear – when he arrived at the stop on Hales Street.

“The bus started to move as soon as he took the handbrake off. Once the bus had started to move Mr Chander held his foot down on the throttle pedal instead of the brake, and that caused the bus to accelerate out of control.

“We suggest that the only possible explanation was that he had become confused over the controls of the bus. He thought that his foot was on the brake, but in fact he was accelerating hard.”

Chander worked for Midland Red for 45 years. Although he officially retired in 2003, aged 65, he was re-hired almost immediately as a relief driver.

The trial continues.