Why were they banned? They're used in the Netherlands which is rife with small bendy streets so if that was the argument it seems to be somewhat spurious.

They sucked basically. A bendy bus takes up twice as much space as a double decker while being half as fun to ride on. Even with double deckers many bus stops operate beyond capacity with multiple buses in contention at a stop, double deckers allow 3 buses to load simultaneously allowing six busloads of people to board in a space that would only allow for 1 bendy bus, essentially tripling the capacity.

They also cause problems for other road users such as cyclists.

Bendy buses work well if your city has wide straight roads. London's roads are neither.

There were some fatalities that got a lot of attention in the media. There was also a problem with fare evasion. Some were catching fire as well. A perfect storm of issues.

The right-wing media at the time latched onto them as the cause of all of society's problems, and Boris Johnson promised to get rid of them if he was elected mayor.

In addition to the other reply's issues, they replaced the dirty and stinking but British-made old Routemaster buses, they were much more accessible to the disabled and babies (pushchairs), they were used successfully elsewhere in Europe, and they use more road space which could otherwise contain an important person's car.

I think they're still used in cities outside London, but that's OK since Daily Telegraph journalists never go there.

Any public transport initiative that in any way inconveniences a car driver gets hate in the UK