The threat to the party in some parts of our country is now existential. But we can progress, as we have in London, by being bold and strong in our core beliefs

• Sadiq Khan is the mayor of London

• Attacking Greens is ‘flawed strategy’

There’s no sugar-coating what happened in the byelection in Gorton and Denton – it’s a terrible result for Labour, coming third in a seat we had held for nearly a century. People often exaggerate the significance of byelection results, but this one does speak to a far-reaching change and fracturing in our politics, which cannot be ignored or wished away.

A political strategy of taking liberal, progressive voters for granted is clearly flawed. The national Labour party and government doesn’t just need to reflect on this result, but fundamentally rethink its approach.

Sadiq Khan is the mayor of London