Being the arrogant bunch of twits we are, us British tend to slaughter anyone else attempting our accent. Poor old Dick Van Dyke is still held as the high watermark for Grievous Bodily Harm on our accent when he set it on fire, put it out with a jet of his own special water and then spread rumours about its mother's promiscuity as Bert the Chimney Sweep in Mary Poppins.
Kevin Costner's go at speaking Blighty in Robin Hood was awful and even the actress who played Daphne in Fraser just sounded weird and she's English while David Boreanaz's stab at Irish in Angel sucked more than his vampire character ever could.
To balance things up, the Radio Times have got stuck into Brits attempting American accents and failing dismally with Michelle Ryan winning the honour for her portrayal of the Bionic Women, which has now been cancelled.
Other bad yank accents included Eddie Izzard in The Richies, Annie Friel in Pushing Daisies and Hugh Laurie in House.
Even to my English ears Michelle Ryan's American accent was rubbish but i was impressed by Hugh Laurie in House especially when his normal accent is so quintessentially English.
I haven't seen Izzard or Friel so can't comment on what they do to the American accent but Michelle, you will now always be known as the Dick Van Dyke of American accents which is actually better than being remembered for being Zoe Slater in Eastenders.
Come to think of it your cockney accent wasn't that hot then either.