Confidential

Looking into the history of gossip magazines, it appears to have been spearheaded by Confidential, an American magazine published from 1952 to 1978

http://gawker.com/5454839/when-gossip-was-gritty-confidential-magazine

http://law2.umkc.edu/faculty/projects/ftrials/confidential/confidentialaccount.html

http://mercurie.blogspot.co.uk/2012/08/naming-names-rise-fall-of-confidential_20.html

it seems to be very difficult to find copies or even online versions of the content itself, but i frequent many a fusty charity shop so I will be keeping a look out

I wonder what the first british tabloid magazine was, that would be easier to find