"The Secret Policeman's Ball" was a 1979 gig - directed by John Cleese - and raising funds and awareness for Amnesty. It inspired - among others - Bono and Bob Geldof to campaign on high profile issues. Now - twenty-seven years after that first show - it's back. "The Secret Policeman's Ball" is at the Royal Albert Hall tomorrow night - with some of the biggest names in music and comedy taking part. Earlier today I went to meet one of them - American comedy legend - Chevy Chase.