In his second answer at prime minister’s questions today, David Cameron asked a question of Ed Miliband:

As we are being kept here to vote on the publication of the NHS risk register, why don’t you ask a question about that?

It seemed like a strange tactic. Why would the prime minister, who has been ordered by the information commissioner to publish the document detailing the potential risks of his NHS bill, want to bring up the fact that he is refusing to comply? Surely this was a subject on which Labour, not the government, holds the upper hand?

Only after the prime minister had put the challenge several times did we find out why he was so keen to talk about it.