John Bercow has condemned populism and those who promise easy solutions to complex problems in Channel 4’s alternative Christmas message.

The former Commons Speaker started his speech describing himself as a “cheerleader” for parliamentary democracy and MPs. “The overwhelming majority work hard to protect and promote the interest of the people they are charged to represent,” he said.

In the five-minute speech, which aired on Channel 4 just before the Queen’s Christmas broadcast began on BBC One, Bercow quoted Winston Churchill and impersonated the veteran leftwing Labour politician Tony Benn.

Bercow, who stepped down in November after more than 10 years in the role, said democracy had taken a pounding: “All around the world, populism and the promise of simple solutions to complex problems has taken hold with a vice-like grip. Don’t get me wrong, it’s crucial for everyone to be free to say what they think and for politicians to respond, but democracy shouldn’t be about decibel levels. An opinion is no more valid because it is expressed more loudly, repeatedly, or abusively.”

He quickly accepted that he has become known for raising his voice, but added: “What bothers me is there are people on the internet and in some newspapers who cannot entertain the idea that anyone can honourably hold an opinion which differs from their own. They are the angels and anyone who dares disagree is the devil who wants the country to be poorer, less free, or less secure. That mindset started to infect parliament too. That is wrong.”

“If democrats show no respect for each other, it just encourages anti-democrats. It’s high time we learned to disagree agreeably.”

He went on to say his best friend was not an extremist, a racist, or a fascist because he was a Brexiter, nor was he a traitor, a malcontent, or an enemy of the people because he was a remainer.

Bercow follows the actor Danny Dyer, the whistleblower Edward Snowden and Brendan Cox, the husband of the murdered MP Jo Cox, in delivering the annual rival to the Queen’s broadcast. Channel 4 has produced an alternative message for the past 25 years.

The speech was delivered from a classroom in Bercow’s children’s state secondary school. He went on to criticise the role social media has played in amplifying hatred, racism, misogyny and abuse.

“As I sit here in my kids’ fantastic state secondary, I have to say I worry about that. Incidentally, if you want to see an example of respectful debate, take a look at the UK youth parliament,” he said. “They spoke well, respected one another, and behaved better than many political campaigners, two, three and four times their age.”

Bercow continued: “Let’s take inspiration from young people. They are the future. Let’s try to re-establish a civility of discourse. It would be good for parliament, for democracy, and for our own mental health – an issue which is finally getting the attention it needs.”

As Bercow’s calls for “Order!” have made him an international celebrity, he ended his speech saying it with a group of schoolchildren.