Finally we have a prime minister again. Harriet Harman has filled a vacuum. We have had little leadership for a year, and suddenly we know where we stand. You are probably appalled, you think she is ghastly, hideous, ranting. But, admit it, at least she is a conviction politician.

She has a view, an agenda and, knowing Harriet, a neatly written out list of goals. In the few days since Ms Harman walked through the door of No 10, she has not stopped. She is everywhere, with her own opinion on everything, challenging Home Office civil servants and bankers’ bonuses. Deputies are not supposed to do this. They are meant to hide under the desk and hope they won’t be hit by a croquet mallet.

The past year has been visionless. Parliament has frittered away its time. Hattie has decided she has won the prize to be Prime Minister for a fortnight and she is going to do something with it. She has not been sneaky, you know exactly what she thinks. You cannot accuse her of dithering or giving mixed messages. She doesn’t do gimmicks, no twittering or YouTube, she just gets out there and says it.

Even if you profoundly disagree with what she believes (and I do), you have to admire her drive and singlemindedness. She has a cogent philosophy. You know what she stands for: sexual equality. Ms Harman approaches every subject in the same way — will it help women? Before she became an MP, she brought the first cases for women under the Equal Pay and Sex Discrimination Acts. In Parliament she drove through women-only shortlists and led the campaign for longer maternity leave. Even the sisterhood takes issue with the way she has tried to fling her handbag through so many glass ceilings, but she has created a debate.

After two years in power, Gordon Brown seems to stand for crisis management and Brussels sprouts. He is spending his summer salving his conscience by doing community service rather than recuperating and planning a strategy for the next year. The Cabinet appears to have given up. Alan Johnson calls himself a “hack politician”. Bob Ainsworth admits: “I don’t try to pretend I am cleverer than the Chief of the Defence Staff.”

Backbenchers are skulking away from their constituencies, fulminating on the unfairness of the expenses scandal. Harriet is unbowed. She may not be the cleverest politician but she is tenacious and she is seizing her chance to change the world. She did not come into politics to ruminate about duck houses or ginger biscuits.

The Tories could have filled the gap this summer. After the Norwich North by-election everyone wanted to know what the government-in-waiting was thinking, but they have gone on holiday: to Brittany, Cornwall and Greece. They have left a scattering of proposed budget cuts, a few hints but no vision.

In some ways Ms Harman is Britain’s answer to Sarah Palin. The thought of her becoming leader is ludicrous, but both have shown up the opposition with their energy and drive and the simplicity of their vision. They are also brave, they don’t care that they are lampooned, they are prepared to take on the big beasts, whether it’s a moose or Lord Mandelson. Peter recognises it. He said in a recent Times interview that he liked “Harriet’s gutsiness".

"I don’t always agree with her but she’s an enjoyable person I can both agree and disagree with.”

A fortnight of Ms Harman is enough. But we should thank her for bringing politics back to Westminster.

Times Recommends

• Please help: maimed children of war want their lives back
• Unlocking the cruellest prison
• Charles named in £81m court battle