A cyclist filmed a London bus driver using his phone at the wheel in slow moving traffic in central London.

The driver was caught out looking at the device while driving down Ludgate Hill, near St Paul’s Cathedral, at 7:30pm on Sunday.

He was filmed by a cyclist, also on a mobile phone, who claimed the driver was placing bets while behind the wheel of the bus which was carrying passengers at the time.

In the clip, the cyclist can be heard shouting: “Are you placing your bets whilst driving a bus with passengers?

"You are out of your mind; you can kill people with that.

“You have to focus on the road. Every time I cycle my life is in danger because of drivers like you.”

The driver replies that he will be sitting in traffic for forty minutes.

The cyclist, who wanted to remain anonymous, said he does not normally go around filming bus drivers but he was prompted do so on this occasion by his "dangerous" actions.

He told the Standard: “I drove a London bus for five years so I am more likely to spot when someone is driving dangerously.

“I had pulled up to the traffic lights and saw the bus moving when he was hardly looking at the road and when I looked closer I noticed he was placing a football bet on his phone.

"I could not believe it!

He said he did not want to share the clip at first, adding "but when I watched it back he did not once acknowledge that he was doing anyting wrong so I decided to report it."

“I have to look out for mine and other people's safety. If that guy caused an accident I would never forgive myself.”

The incident has been reported to Transport for London, which has launched an "urgent investigation".

Mike Weston, TfL’s Director of Buses, said: “Public safety is always our top priority.

"We are conducting an urgent investigation into this incident and will take appropriate action.”

The bus company Arriva is also investigating the allegations.