Keir Starmer has made life difficult for Boris Johnson this week with his demand for a circuit-breaker lockdown. But the Labour leader’s colleague Andy Burnham is currently presenting a far greater threat to the Prime Minister. On Thursday, the Mayor of Manchester gave a furious speech in which he accused the government of being ‘willing to sacrifice jobs here to save them elsewhere’ while treating his area like ‘canaries in the coalmine for an experimental regional lockdown strategy’.