Posh, 33, tops the Ten Titans Of Taste-Free Terrors in his Worst-Dressed List for 2007.
Infamous Mr Blackwell also slams UK star Amy Winehouse, 24, for her 'part 50s car-hop horror' style.
'Let it be said, however, that my criticisms are based purely on their fashion flaws,' says the style commentator. 'I'm sure they're all wonderful people beneath the deluge of dreck they drape themselves in.'
Mr Blackwell - who is 86 this year - does love the way some Brits dress - he praises Jemima Khan, Helen Mirren and Kate Middleton.
Britney Spears usually makes it into his Ten Worst Dressed Women but was missed off the latest compilation.
'I felt that it was inappropriate at this time to make comment,' he explains, 'her personal life is in such upheaval.'
