She's definitely rising to the occasion, Harriet Harman. Full of energy, she was at PMQs, standing in for the globe-trotting PM. She demonstrated great verve, conviction and some charm as she spun off deft lines at her opponents. "More! More!" everyone cried at the end, though the Tories did so for complicated reasons.

Her gesturing was very good. She pointed, she held up one flat hand, she pushed her pen at the opposition. She meant it to sting all right; they didn't like it one bit. And she has very nice skin, you know. I've often thought she could lead the party, in the event of the World Saviour stepping into a chariot of fire and being taken away to glory.

To which end, there was a poll recently. Members of the public and politicians were shown photos of various candidates and asked to rate them for suitability to lead Labour. Ed Balls was in the line-up, along with a rat called Fang, a Big Mac with cheese, a bust of Joseph Stalin, and a basket of figs from Waitrose. Harriet didn't come last but she wasn't in the front-runners, I'm sorry to say. Maybe Jack Straw will make it after all? Though it's hard to think Alan "I'm Just Not Up To It" Johnson could fail, if he stood.

Harriet's problem may have been illustrated by William Hague's elegant riposte to her thrusts on inheritance tax. "I can see why inheritance would be of interest to the niece of the Countess of Longford," he said. There was the sound of an angelic sword being thrust into holy water as the Labour back benches absorbed this.

Hague also planted a barb in on the subject of the mortgage support scheme. He is nothing if not resourceful. Geoffrey Robinson was called into the argument: "He knows a lot about loan guarantees," Hague threw in. It was a reference to Peter Mandelson's first resignation too complicated to go into here. He is worth every penny of his after-dinner fees.

Harriet dealt with the jokes in the way that disables his best sallies: she laughed at them. He mentioned Mandelson's trip to Brazil and asked whether he shouldn't be implementing all the crunch initiatives instead of "unpacking his Speedos on a Latin American beach". Harriet's teeth came forward in a horsey, schoolgirl way as she "rocked with laughter". It looked completely genuine.

Ah, we can but dream. Hague did ask three times whether she agreed with Mervyn King's injunction to Gordon Brown: no more trying to spend a way out of the recession. And three times Harriet harried him about Tory tax cuts and their "millionaire's manifesto". This split with the Bank of England is bad for Brown – but Harriet was brave enough for both of them.

simoncarr@sketch.sc