Donald Macintyre's Sketch: A dog that didn't bark. Or bite. Or give us a story

Matthew Barzun, United States ambassador to the United Kingdom (Getty Images)

One good thing about being the US ambassador to London – apart from living in a natty neo-Georgian pile set in 12 acres of Regent’s Park – is knowing you can’t be worse than your most famous predecessor in the past century.

Whatever Joe Kennedy’s other claims to fame – father of Jack, Bobby and Ted – he was a terrible envoy for FDR, warning everyone that Britain was “gonna get thrashed” by Hitler and that the US should stay out of the war. But if the wartime appeaser revelled in being monstrously controversial, his young present-day successor has arguably swung the pendulum back too far.

Matthew Barzun is polite, charming even. But if nothing else he is proof that you don’t have to be a career diplomat to turn blandness into a fine art.

Did he agree, he was asked at Tuesday’s press gallery lunch, that Kim Kardashian was a “terrible role model”? “I’ve nothing interesting to offer there,” he said apologetically. What about dual-citizen Boris Johnson’s IRS problem? Well, an American was entitled to privacy on taxes, health and “other information”, so “I won’t comment on that”. But the principle? “Well, we have our rules and we expect people to play by them.” But he was not talking about any “specific case”.

What of Facebook, Google and Amazon’s reluctance to pay UK tax? “We [governments] made these rules and they are playing by them…” Were we right to blame Facebook over Drummer Lee Rigby’s death? “No… I don’t think it’s fair to pin everything on the private sector, nor is it fair to say they have no responsibility in trying to come up with solutions.”

What about British defence cuts? By now, we were desperate for him to say something like: “Yes. Instead of relying on us, you snivelling freeloaders should be paying your way.” Instead he was “sympathetic” because the US had similar problems.

OK, he made a good self-deprecating joke about being described as a “potato with hair”. And he reiterated US policy that the UK would be better off in the EU, but, of course, it was all “entirely up to you folks”. So, seemingly a nice guy. But if he really is – as described by a White House aide – “a big dog that hunts in the long grass”, he doesn’t, on yesterday’s showing, have much bark. Or bite.