The band of 11 who broke Corbyn and May on Brexit

For Mr Corbyn this was to announce his support for a second referendum if he cannot get the Brexit deal he wants. The risk of the People's Vote band in parliament following Chuka Umunna et al out of the door was simply too great. In reality, a plan to hold another referendum probably won't get through parliament, so this is a promise Mr Corbyn might never have to actually keep. But that he was forced into making the pledge for fear of a split is ample proof that this was the week traditional command-and-control party politics was turned on its head.