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like Boris he did seem to become PM just because he felt it was his right, with little or no idea about what he would actually do in the job. Resigning directly after the Brexit vote was a craven abdication of responsibility.

I think Cameron and Osborne were ideologically in favour of austerity and genuinely relished the opportunity to roll back the easier fiscal policy of the Blair / Brown years.

Once the Brexit gamble had gone wrong I don't think it was credible for him to stay on and implement a policy he had unambiguously campaigned against. Although it would have been nice if he'd delivered the softest of soft Brexits (BRINO?) by way of apology...