Stephen Green's appointment sends a message to Conservative MPs: "Because you're not worth it."

By Paul Goodman

It's essential to Parliamentary Government that MPs are laymen and women - in other words, generalists rather than specialists.

This isn't just because as members of the legislature they'll have to cover a vast range of matters as Parliamentarians, ranging from voting on whether or not to support a war to sorting out a constituent's housing problems.

It's also because they may also become members of the Executive - Ministers.  It sounds counter-intuitive to say this.  Shouldn't the Minister for Health be a doctor, the Minister for Education a teacher, the Minister for Agriculture a farmer, and so forth, so that each knows what he's talking about?

But asking the question highlights the problems thrown up by the suggestion.  It may not be a good idea for the Minister of Education to be a teacher, after all.  Sure, he'll know something about schools (at least those he's worked in) and a bit about education generally .

However, he could also be an instrument of producer capture - an ugly phrase for an ugly thing.  He may not be able to throw new light on how the education system should be run.  He may also not have the bundle of skills that being a successful Minister requires - convictions, energy, determination, cunning, the ability to make decisions, handling colleagues and the media, and so forth.

Stephen Green is clearly an exceptionally gifted banker and businessman.  The Guardian reports today that he "is expected to step down from the bank to take up the role of trade minister in the coalition government... after reports that David Cameron had been struggling to persuade a major City figure to take up the post."

There's sometimes a case for bringing a talented outsider into the Government as a Minister in the Lords - although, in general, Ministers should be elected.  But recent experiments have not been successful.  Remember Gordon Brown's former "GOATS"? ("Government-of-all-the-talents")?

At best (Lord Darzai, Lord West), none made a Ministerial contribution that couldn't have been offered by a capable, middle-rank Member of Parliament.  At worst, they either irritated their colleagues by epic grandstanding (Lord Mallloch Brown) or soon left the Government to spend more time with their money (Lord Jones...the last big business figure to be appointed).  In short, they were fish out of water.

So appointing Stephen Green would be a mistake, for three reasons.

• First, because it's suspect in practice.  Green's no more or less likely to succeed as a Minister than any other newcomer, since he's no experience of handling legislation, or working in a world in which public responsibility and accountability are required.
• Second, because it's bad in principle.  The more people are appointed as Ministers to the Lords, the greater the diminishment of accountability to the voters.  In any event, the Department already has a Lords Minister, Baroness Wilcox.
• Third, because it sends a message to each backbench Conservative MP, as I've written before - namely, that the Prime Minister thinks that he's not up to the job, and that none of his colleagues are, either.  David Cameron is sending his MPs the opposite of the famous old L'Oreal slogan.  His message is: "Because you're not worth it."  This is, as the Whips would put it, "unwise".