The Good Morning Britain presenter, and one half of TV legends Richard and Judy, told Kate Thornton on White Wine Question Time that he used to go on the social media site after coming off air from the couple's Channel 4 show for what could be a 'civilised' and 'polite' discussion.
The couple hosted the chat show Richard and Judy in a 5pm slot on Channel 4 from 2001 until 2008.
Richard compared social media in the show's later days to a new pub opening round the corner full of strangers who were 'on the whole really nice, interesting people'.
He said: "Now it's this horrible, horrible pub, that you the moment you walk in people are throwing drinks at you. [And] throwing food at you, and swearing at you and letting your car tyres down in the car park outside. So you don't go to the pub anymore. So I don't go on Twitter anymore. It's just pointless."
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Judy wondered if there should be a 'compulsory Twitter charm school'.
She said: "Before you go on Twitter, you [should] have to pass a test in politeness and niceness."
Richard said people used to like the fact they could talk with the presenter of the show they were tweeting about, and that the conversation could be critical in an 'intelligent and sometimes completely accurate way' or could also be complimentary.
He told Thornton he used to go on social media a couple of hours after the Channel 4 show had come off air, two or three times a week, 'just to see what people were saying about the show that night'.
"It's a great shame the way that social media has toxified in the way that it has," he said. "It was always interesting [when he first went on]. And sometimes it was critical, but it was critical in an intelligent and sometimes completely accurate way.
"Or it would be complimentary. But it was always a good discussion, I would join the discussion. And we'd kick it around. And people liked the fact that they could talk to the presenter of the show that they were talking about. And it was civilised and it was polite. You got the occasional stupid remark."
Thornton added that the site "gives a voice to the voiceless. And while that's great, it also gives a huge volume button to a********."
Recalling a Graham Norton interview he had read, Richard said the comedian had said he could go on to the social media site and post a positive message saying what a nice morning it was, count down from five to zero, and already have a reply saying 'easy for you to say it's a beautiful morning, you rich bastard.'
Richard said: "You just cannot win."
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