Joan Smith: If Sally Bercow were a bloke, she could be Mayor of London

She admits she drank too much at Oxford, had one fling after another in her twenties, and makes no secret of her political ambitions. After acknowledging all that in a newspaper interview, can Sally Bercow expect us to take her seriously? The Conservative MP Nadine Dorries certainly thinks not.

A couple of days ago, she accused Mrs Bercow of "eroding any progress Parliament had made towards restoring its lost integrity and authority". I can't help thinking Ms Dorries is confused, as well as insufferably pompous: John Bercow is the Speaker of the House of Commons, but his wife isn't even an MP. Her remarks about long-ago binge drinking and one-night stands have nothing to do with the present condition of Parliament, just as she can't be blamed for a crass article her husband wrote 23 years ago in a student magazine.

To judge by the furore Mrs Bercow's interview has caused, you might think she'd owned up to joining a notorious drinking club, crawling through the Botanic Garden in Oxford to evade police dogs, and going on to become a serial adulterer. That was Boris Johnson, erstwhile Tory MP and current Mayor of London, and it hasn't done him any harm. But Boris is a posh bloke, so the rules are different for him and members of the Shadow Cabinet who also joined the Bullingdon Club at Oxford. In yesterday's Times, Giles Coren even proposed a Christmas party game: Have You Shagged the Speaker's Wife? "Because the word is, everyone has". Leaving aside sneering, puerile misogyny, Mrs Bercow isn't a Tory and she would like to become a Labour MP, which makes her a traitor in Conservative circles as well as an embarrassing wife.

For decades, a sure way for Tory women to get into Parliament was to marry an MP instead of struggling to get a seat of their own; it has encouraged a view on the Tory benches that the natural order of things is for MPs' partners to stay in the background. This simply cannot be sustained in the 2lst century. I have to declare an interest here since my own partner is an MP, but he's Labour and doesn't think we should be joined at the brain.

David Cameron keeps trying to persuade us that the Tories are a modern party, but they still don't seem to understand how ordinary people live. So Mrs Bercow drank too much nearly two decades ago, went to AA a couple of times and stopped drinking? Good for her. She sometime fell asleep on the Tube and missed her stop? Who hasn't? (All right, it doesn't happen often to bankers and former members of the Buller, but I'm talking about the real world.) What about the torrid sex with a cross-dressing cage-fighter? Oops, that was Katie Price.

What Mrs Bercow actually said was that sometimes she had gone home with someone she'd just met in a bar. She wouldn't recommend it to her daughters – she'd warn them off using unlicensed minicabs as well – but isn't exactly material for a mini-series.

The reason Mrs Bercow has put all this in the public domain is that she's already been accused of being untruthful about her CV, an accusation she denies, and she's hoping there are no "skeletons" that might damage her political ambitions. It wouldn't have received so much attention if Mr Bercow weren't hugely unpopular with Tory colleagues – I'm amazed at how scathing some are about him in private – and they're trying to damage him through her. That's nasty old-fashioned politics, and Cameron's Conservatives need to recognise that the Speaker's spouse isn't Caesar's wife.

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