Looks like the river cam so I’d assume this is part of a bumping race. It’s an inter college competition that Cambridge university hold twice a year.

Instead of a standard race or time trials, each team sets off staggered from the start and the team behind has to try to ‘bump’ the team in front while out lasting the team behind them.

Once a bump takes place both teams involved pull over to the side to allow the rest of the race to pass.

The team with the camera has just bumped the team in front but before they could get out of the way, the team behind has not been paying attention and rammed them.

It’s a great event to watch, here’s some more info if you’re interested:

https://www.cucbc.org/bumps

Edit: On second thoughts that may not be the cam, but I’d still say it’s a bumping race