There are a number of people who are being considered for it.
"John Richard Whiteley", Officer of the Order of the British Empire/OBE, Deputy Lieutenant/DL was an English people/English presenter/broadcaster and journalist, best known for his twenty-three years as host of the game show Countdown (game show)/Countdown. Countdown was the launch programme for Channel 4 at 4:45 pm on 2 November 1982, and Whiteley was the first person to be seen on the channel (not counting a programme montage). Despite his intelligence, Whiteley enjoyed projecting the image of an absent-minded eccentric. His trademarks were his jolly, avuncular manner, his fondness for excruciatingly bad puns, and his bold, sometimes garish wardrobe.
Thanks to over twenty years' worth of nightly instalments of Countdown as well as his work on the Yorkshire magazine programme Calendar (News)/Calendar and various other television projects, at the time of his death Whiteley was believed to have clocked more hours on British television screens—and more than 10,000 appearances—than anyone else alive, apart from Carole Hersee, the young girl who appeared on the BBC's iconic Test Card F.More Richard Whiteley on Wikipedia.