The Sketch: Deputy Harman is all liability

As the Sketch was the first to issue derivatives in Harman a year or so ago, I have a fund manager's update for current asset holders. You don't have any assets. They're all liabilities.

Your investment contains such toxic sub-prime credit structures that it will put owners into the poor house. You bought into the AAA-rated issue of human rights and equality, and the fact she has a block vote in the party and unions on account of her husband. There was the AA-rated performance in the Commons against William Hague. And for those of you who wished to believe it, she had been granted an A-rated record in office with her Bills, or Acts.

It wasn't disclosed in the prospectus that the market was mad at the time, the rating agency had been drinking heavily and everyone was being paid whether or not the analysis was right.

The fact that Harriet Harman is the Tories' preferred leader says much, and her performance this week – culminating in PMQs – says the rest. She has gone the way of Miliband (sitting behind her spending far too much energy busily organising his face into appropriate expressions).

Here are three reasons to sell whatever Harman you have.

First: When things get serious in the Commons the noise level rises. The leader needs either to be able to quell the noise by power of personality, or to cut through it with a pig-squeal of a voice. Thatcher had both. Harriet has neither. The voice is the most important thing in Commons life. If you're hung like a cocktail sausage you'll never be a porn star; if you've got a voice like Harriet's you'll never be able to lead the party in Parliament.

Second: Leaders in waiting don't get things utterly wrong in the Commons. Elfyn Llwyd asked: "Who nominated Sir Fred Goodwin for a knighthood and why?" A wickedly difficult question for a minister to answer. Harriet made something up. The Prince's Trust had nominated him for charity work, she said. I noted down, "Brilliant! True?" It was untrue. Fred was knighted for services to banking. She'll have to retract her "mis-speaking" in the Commons. "I screwed up," she will say, thinking it'll increase her share price. It won't. She was under pressure, she made something up to get out of it. That kills leaders.

Third: You have to beat William Hague every question time. He's only a deputy and leaders beat deputies. She usually manages it, this reluctant judge agrees. But yesterday she was slaughtered. Hague finally hit the right nerve. The Government was exhausted, directionless and had lost the confidence of the country, he said. When that happened to Chamberlain, Churchill stepped in. When it happened to Eden, Supermac took over. And then, as all urbane, amused Labour MPs chuckled (or both of them did), he concluded: This could be Harriet's moment!

They all hated it. But they hated even more the fact that Harriet's response included the words, "Every county court now has a help desk."

Her rehearsed jibes came out, but they were contradictory. They were i) The Government was saving the country while the opposition dealt in gossip. And ii) Hague had made £30,000 from the Royal Bank of Scotland by giving just two speeches. That wasn't gossip?

So. No pig-voice; talks rubbish; is a natural deputy. Who's for Harriet? Tories!

simoncarr@sketch.sc