By Nick Assinder Political correspondent, BBC News website

Johnson is not very popular in Liverpool

Oh to have been a fly on the wall when new Tory leader David Cameron gave Boris Johnson a frontbench job.

Cameron: "Now then Boris, you're a good chap and a first class brain and I am going to give you the job looking after Britain's universities, including the places where sound chaps like us go after Eton.

"But please, please, please, no more gaffes. No more dissing Liverpool, no more affairs, a bit less telly and larking about and a bit more knuckling down. OK, what do you say?"

Johnson: "Gosh. Absolutely. Will do. Suitably grateful and repentant and all that.

"Suppose the day job will have to go. So it's thinking cap on and best behaviour from now on."

And off Boris might have shambled, all quizzical expression and bicycle clips, to make remarks about fat Germans and Everest.

[Cameron] might not even mind a little bit of edge-of-the-seat from his new frontbencher so long as he delivers the goods in terms of policy

Fantasy, of course - except the bit about fat Germans. Probably.

Boris Johnson is not only one of the brightest of the bright young things Cameron wants to give his party a new image, he is also about the only Tory face with the instant recognition factor.

That may not always be for the best reasons, but Boris is undoubtedly a character - even a celebrity - in a party much in need of a bit of showbiz.

Cameron knows he is a risk, and he can be a bit of a loose cannon. But he also knows Boris will attract attention.

All he has got to ensure is that it is the right sort of attention.

He might not even mind a little bit of edge-of-the-seat from his new frontbencher so long as he delivers the goods in terms of policy - which Boris certainly has the ability to do.

It was also certain Boris had to give up his post as Spectator editor.

Infamous piece

Carrying on with both jobs would have been an accident waiting to happen - as it did last time around.

As editor he has to take responsibility for anything which appears in the magazine, just as he did with the infamous Liverpool piece which he did not write himself.

Also, it would only have been a matter of time before the magazine found itself at odds with the Tory party or its leader over an issue or policy, leaving Boris in an impossible position.

So the Spectator goes and Boris will now devote all his energies to his new post.

After all, he would not want to follow the example set by a couple of Labour frontbenchers, and lose a frontbench job twice.