This San Francisco newspaper has the story and the emails:

It appears controversial radio host, Michael Savage, was the target of an intentional ban to the UK based on racial and religious grounds, according to the London Daily Mail.
Emails obtained under former Home Secretary Jacqui Smith show that Savage, (real name: Michael Weiner, who is Jewish) was placed on the ban-list and would provide “balance” since Muslims dominated the list. The emails were directly linked to UK Prime Minister Gordon Brown and Foreign Secretary David Miliband, according to the paper.
Savage was placed on a ban-list to the UK in May by Smith, who has since resigned. Savage subsequently sued the UK and Smith for defamation of character and libel. According to reports last week, he was taken off the list, but Savage told me exclusively that no such action had occured.
He also stated that his lawsuit would proceed and hinted that both the US and UK govt. officials were behind his placement on the list.