John Healey quitting defence puts a time bomb under No 10. He is a loyalist: this is no ordinary departure

<p>He served through the eras of Blair, Brown, Miliband and Corbyn in a party that knows and respects him. It will matter that even his patience has run out </p><p>John Healey is not a rash man. Slow to anger, calm in a crisis, loyal and yet beneath it all, formidably determined. He stuck at it thro