Jeremy Corbyn's performance at prime minister's questions today was his best since he became leader. His questioning was relevant, informed and difficult for Cameron to respond to. He showed concern for the victims of flooding while raising vital and specific questions about the government's failure to adequately fund a whole series of flood defences.

By contrast Cameron came across as flippant and even childlike in his responses. While Corbyn asked questions about pump capacity and flood compensation, Cameron answered with embarrassing Shakespeare gags about the Labour reshuffle.

The prime minister's replies to detailed questioning was often simplistic to the point of farce.

Asked about cancelled flood defence funding, Cameron replied that: "We have got the strength to tackle these floods and we will do it in a proper way." Asked why specific projects had been cancelled, he replied that: "We're putting in the money. We're putting it in quickly." Asked about his plans to prevent devastating future flooding, he replied that things would be okay because: "We've got a strong economy and a strong country." Pushed by a Labour MP on his record on floods, he replied that "what I said absolutely stands good".

Although regarded as a serious and professional politician, at times Cameron's language had all the linguistic sophistication of speech by Donald Trump. All he needed was a "Make America great again" baseball cap and the effect would have been complete.

The disparity between the quality of Corbyn's questioning and Cameron's GCSE-level responses could not have been clearer. And yet of the two men, it will be the Labour leader who will most feel the pressure following today's PMQs.

His botched handling of his shadow cabinet reshuffle and the series of resignations that have followed this morning, will completely overshadow any positive coverage he might otherwise have received for his performance today. If PMQs is featured at all in tonight's news bulletins, it will almost certainly be clips of the prime minister making gags about Labour's woes, rather than Corbyn's questions about the woes of UK flood victims.

And yet, while Labour can complain about this, the truth is the fault is largely their own. After a disastrous few weeks for large swathes of the country, the opposition should really have focussed all their efforts this week on putting the prime minister's reputation under several feet of water. Instead they have allowed him to sail off into the distance once again.