[dijit]

There's no rule that says that, in fact the rules in the UK are that you can pay people below minimum wage if they're under a certain age.

I think there are also some tax incentives that are designed to make employers more friendly to the idea of hiring a young workforce - all to offset the "cost" of training people, but of course this is just used by mega-corps to have a perpetual stream of extremely cheap labour for frontline staff. (Argos, McDonalds).

So it's possible that not only do they not pay tax, that also their employment is partially subsidised by tax.

[roryirvine]

Even if below the income tax threshold, they might still be above the Class 1 NICs threshold (which is £250 or thereabouts).

But no matter how low their earnings, all employees must be registered for PAYE from age 16 onwards and will receive an annual P60, as well as a P45 when they leave.