The bus driver was employed by Arriva and was operating one of their Original London Sightseeing open-top services - certainly an original sightseeing tour of the wrong kind was being displayed.
The London Standard said that witnesses told how the driver of the Original London Sightseeing Tour bus got out of his cab to confront a white van driver after an angry and expletive-filled exchange in front of passengers and pedestrians. It would appear the white van driver cut the bus driver up.
An onlooker was quoted as saying, "The white van driver got out and went up to the cab. He had his mobile phone and was going to take a picture. Then the bus driver got out and just went crazy. He was definitely the one throwing the punches. He chased the van driver under the bridge and he dropped his phone at one point. I couldn't believe it. There were three tourists sitting on the bus just looking on confused."
Arriva have opened up an investigation into the incident although said that no one has currently made a complaint to them.
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Luckily such outburst from PCV professionals are very rare indeed; although as recently as last month footage taken in Peterborough bus station by youths captured an incident where a Stagecoach driver was seen attacking a 50yr old drunken man. The driver was later sacked we understand. Click here to see the article on the Peterborough Evening Telegraph's website, where the actual filmed footage can be viewed.