He achieved a succession of scoops, and was responsible for training up a generation of young journalists, including the gossip columnist, Nigel Dempster.
Callan's amiability and nose for a story made him a favourite of actors and publishers alike, and he interviewed virtually every major Hollywood star in the last forty years, and members of the British royal family.
[citation needed] The intention was to contrast the urbane Callan with the less couth Street-Porter, whose accents were respectively known to studio engineers as "cut-glass" and "cut-froat".
The programme was the first in the UK to combine interviews with celebrities and heavyweight political figures on the same show, blurring the line between classic British comedy and analysis of international affairs.
As one of the last representatives of old Fleet Street he cut an unmistakable figure, clad in pinstriped suit and trademark spotted bow tie regardless of geography or climate.