Synthetic double-standards

I see Iain Dale is full of indignation about the "synthetic outrage" over Jeremy Clarkson's insult to Gordon Brown, on the basis that much worse was said about Margaret Thatcher on television. But while cruel jokes were certainly made about Thatcher's appearance and her voice, were any of them overtly racist? If a Scottish TV presenter, say, had attacked Thatcher solely on the basis of her Englishness, would that not have caused a great deal of offence and perhaps bewilderment in England? It appears that the acceptability of 'Jock-bashing' is taken as so much of a given by south-of-England-based media types that the nature of what they're doing just doesn't seem to register with them any more. The proof of that is that Clarkson appears to have apologised for mocking the Prime Minister's disability, but not for mocking his nationality.