Can I point out an important quote in the Telegraph article
There is no suggestion Mr Moyles has avoided tax.
That said, as I understand it, being freelance is, in many ways, one big tax efficiency scheme.
You set up a company, and arrange to have your fee paid to it as a business to business transaction - the "employer" is buying a service from your company rather than employing you. You then get paid via a combination of dividends from the company and salary from the company.
Your company can then claim tax relief on various expenses such as running a car, equipment etc.
If your accountant isn't making sure you don't pay excessive amounts of tax, they're not doing their job. But there is a balance between being tax efficient and taking the piss.