Sarah Sands: Lumley for president? I'd keep the Queen

She is magnificent, but too risky to wield power

A high-end argument for the monarchy is that the elected alternative would be worse. The Queen or... Simon Cowell. There is no one apart from the Queen who could unite the country, be a symbol of all our history and values, rise above petty politics in favour of duty and honour, the argument goes.

Until this week, when Joanna Lumley assumed leadership through divine right. She has stormed No 10, whipped ministers into line beyond the dreams of a Malcolm Tucker and without an expletive. Her expression is radiant scorn.

Lumley is a towering rebuke to an exhausted government, filling its pockets as it heads for the exit. There are three reasons why Joanna Lumley is a far more impressive leader than those in power.

First, she believes in something, and her intuitive conviction is shared by the electorate. Like all great leaders, Lumley answers a yearning that the people have barely formulated. Without a single consultant or YouTube adviser, Lumley got it. Gordon Brown has been endlessly fretting over what it means to be British. Lumley solved it one sentence: "Ayo Ghurkali."

She speaks for an old-fashioned strain of Conservatism which David Cameron would not have dared embrace. She extols the virtues of the military and the Commonwealth. She made an implicit argument about immigration: it should be based on allegiance to the Queen. We hardly dare ask this of our MPs, let alone foreign workers.

The pukka tones of Lumley were echoed by the kind of people who listen to Radio 5 Live. Let the Gurkhas stay because they respect the British way of life. And if we need to make a bit of room, why not swap Gurkhas for burqas? Cameron has urged his party to move into the modern age, but Lumley has offered an alternative: late Victorian.

Second, Lumley has no conventional political ambition, but she has sensed a power vacuum. In the early Blair years, I doubt she could have seized all the levers of government without resistance. She could not have ordered a wretch like Phil Woolas into a press conference, shaken out her skirt to find him – "Where are you, Mr Woolas?" – and then dismissed his career as futile.

Just before Caesar's death, there were strange omens, including sightings of a fiery figure fighting. Joanna Lumley, in other words. To mix my Shakespearean references, Brown is also Macbeth, unsure of his own legitimacy, fighting the spectre of his predecessor, while the person who does for him comes from an unexpected quarter.

There is a third reason why Lumley has performed so magnificently. She is an actress. It is as natural for her to greet the cameras as it is mortifying for the vole-like Woolas.

Yet we need Woolases as well as Lumleys. The legal processes which she splendidly discards are a safeguard. The terms to which the Gurkhas signed up were not generous, but they were clear. Lumley is a wonderful woman, but the Queen is less risky as a national figurehead.

Sarah Sands is deputy editor of the Evening Standard