The Camerons' nanny isn't the scandal here...

The whole subject of domestic work is beset by prejudices about class, race and gender

Gita Lama, a long-term nanny employed by Samantha Cameron, arrives for work at Downing Street (Rex Features)

I can't say I care much whether David and Samantha Cameron employ a nanny. Gina Lima has been with the couple for several years, arriving when they needed help with their disabled son, Ivan, and staying on after he died in 2009. The length of time she's worked for the family suggests they have a good relationship, and I'd be astonished if she wasn't paid properly or given sufficient time off.

There is a scandal about domestic workers in this country but the case of the Camerons' nanny isn't it. Lima, who is from Nepal but became a British citizen in 2010, apparently joined the family via an organisation called Kalayaan, which helps migrant workers escape abusive employers. It's based in Notting Hill, where the Prime Minister has his London home, and its website describes the exploitation – physical, psychological and sexual abuse, low pay and long hours – suffered by many workers.

I'm sure Lima is finding public discussion of her circumstances uncomfortable but she isn't the only domestic worker – nor are the Camerons the only employers – to come under scrutiny. Nick Clegg's discomfort with the subject was evident on his LBC phone-in. "I have a lady who has a Belgian passport who helps us," he observed awkwardly. Two more ministers were dragged in yesterday: it was "revealed" that the Home Secretary, Theresa May, has a Brazilian cleaner who now has British citizenship, while the Chief Secretary to the Treasury, Danny Alexander, employs a Portuguese cleaner.

As my colleague John Rentoul notes today, the current row was sparked by a sentence in a speech by the new Immigration minister, James Brokenshire. But it's a ritual that plays out periodically on both sides of the Atlantic, targeting not just politicians who have unknowingly employed an illegal immigrant (as Brokenshire's predecessor, Mark Harper, did) but those who have hired foreigners perfectly legally. There isn't much public sympathy for either category, but that's because the whole subject of domestic work is so beset by prejudices about class, race and gender.

People who work in offices cleaned by minimum-wage migrants sneer at the Camerons or the Cleggs. The fact that most of this labour is done late at night means we don't think much about the people who do it – or their working conditions. I suspect Alexander's cleaner is treated better than most, but who cares when there's an opportunity for political point-scoring?

What's telling about these controversies is the outcome. A politician may be embarrassed, but it's the worker who risks most. In 2009, Labour's attorney general was revealed to have employed an illegal immigrant from Tonga as housekeeper. Lady Scotland, who earned more than £100,000 a year, was fined £5,000 for failing to keep copies of relevant documents. Loloahi Tapui, who was paid the minimum wage of just over £6 per hour, was given eight months in prison and sent back to Tonga.

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