Downing Street is acutely aware that one of the biggest dangers to this government is losing voters’ trust. As I say in the Sun today, if people come to see this administration as just another bunch of politicians who don’t do what they said they would, then it is doomed.
Number 10 also knows that Boris Johnson’s opponents love to attack him as ‘untrustworthy’. This didn’t hurt him too much at the election because voters regard most politicians as untrustworthy. But if there was a clear and compelling example of him breaking his word to voters then that could change, and very quickly.
The whole emphasis on promise-keeping is bad news for Heathrow and the third runway. In 2015, Boris Johnson promised to lie down in front of the bulldozers to stop it being built. So, if the bulldozers move in on his watch it will be acutely embarrassing for him. You can just imagine the split screen of his word and them arriving.
This is one of the reasons why I think the third runway won’t end up happening. If in the next few weeks the Mayor of London wins his judicial review against the decision to go ahead with it, I doubt the government will appeal the verdict.