Today was the day the Shadow Chancellor’s influence on his leader made itself known. After Prime Minister’s Questions, MPs, journalists and viewers were scratching their head at Jeremy Corbyn’s failure to mention the junior doctor’s strike even in passing. Such an open goal, you might think, given the government’s difficulties on this one.

But no, not a sausage. The reason lies with recently reported comments by John McDonnell that from now on, in principle, every single strike will be officially supported by the Labour Party.

Corbyn clearly decided he didn’t want to give the PM the opportunity to give Labour a kicking over a needless foot-in-mouth gaffe. At least, not again.

So instead the man recently described not so much as a Leader of the Opposition as a bloke who runs a second hand camera shop went on the subject of housing. How dare the PM suggest that life on a sink estate was anything other than marvelous, what with all the community spirit and solidarity you can find dumped next to the old sofas and the dog crap? “We’ve built more houses than the previous Labour government!” Dave responded triumphantly. But in this he fails to understand his opponent. Corbyn is no more likely to defend the record of the last Labour government than Cameron is. You could almost see Corbyn shrug as if to say, “Well, there’s a surprise…”

All six of Corbyn’s questions focused on housing. Most of them, naturally, involved getting indignant on behalf of social housing tenants who were on benefits. But one of them, surprisingly, was about home owners. MPs on all sides stopped talking to each other and actually paid attention for a few seconds. “Will he confirm that home ownership has fallen since he became Prime Minister?” he asked in the same tone of voice he might ask a prospective buyer to admire the shutter action on a Nikon SLR.

Cameron looked suspicious. After all, it could have been a trick question – was it a criticism or a compliment? You can never be sure with Comrade Corbyn.

Cameron, doing his best to channel the Iron Lady, used his answer to Corbyn’s last question to make a bombastic case for working class aspiration. Strong stuff, and if you closed your eyes, you might actually have believed he meant it. Their exchange ended without either man breaking sweat. Corbyn is more relaxed every week, which is what happens when you know the bar’s been set so low. Cameron never once seemed remotely ruffled. He’s good, you’ve got to admit it – it’s just that he might be even better if he were pushed by someone he actually took seriously.

There was a telling intervention from the Scottish nationalists leader at Westminster, Angus Robertson, who echoed the universal and unanimous view of Scots by demanding more immigration. Foreign graduates should be allowed to stay in Scotland even if they’ve only secured a job in the local McDonald’s, he told Cameron, who naturally disagreed. They should get a graduate level job after leaving university or face getting trussed up and dumped on the next boat home, he didn’t quite say.

Robertson’s party colleague, Tommy Sheppard , who used to work for the Labour Party and now owns a chain of comedy stores, asked a worthy question about pensions that didn’t even mention Scotland (!). I only mention him in order to ask if anyone else has noticed his astonishing resemblance to a bird of prey? An osprey, perhaps?

It was only at 28 minutes into the (supposedly) half-hour session that the first mention of the government’s “long term economic plan” was made, this time by the reliable Andrew Bridgen of North West Leicestershire, much to the relief of the whips and to the wry cheers of the back benches.

Finally, wee Alan Duncan managed to depress us all by warning the House that the recent massive falls in oil prices might well mean cheaper prices at the pumps, but don’t celebrate yet because actually it could mean the end of civilization as we know it. So at least there’s some good news if you’re a Green…