Donald Trump’s famously-long speeches are getting longer as his list of enemies grow, said a communications expert.

As the US president’s re-election campaign continues, his speeches have clocked in at an average of 80.7 minutes compared to 59 in 2016.

The longest speech ever delivered by Mr Trump was a two-hour long rant during the 2019 Conservative Political Action Conference (CPAC). He also holds the record for the longest average speaking time at State of the Union addresses.

Brian Ott, a Texas Tech University professor of communications and co-author of The Twitter Presidency: Donald J Trump and the Politics of White Rage, said: “An overwhelming percentage of his discourse is about attacking others, and he simply has more enemies now.

“He uses the campaign rallies to air grievances and he’s just got more grievances at this point and never lets go of anything.”

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Mr Trump’s long-winded speeches have driven away even the staunchest of supporters, as seen during a 67-minute speech at a North Carolina rally earlier this week where dozens of people who arrived early to bag prime audience seats left some 20 minutes before he was finished speaking.

At a recent rally, he told audiences he could be presidential in his speeches, but chooses not to because it would be “boring”.

“It’s easy to be presidential but only have about three people in front of me,” he said before breaking into a monotone imitation of a droning politician.

“Doing this takes far more talent than doing that. Doing that is very easy. This is not easy.”

His campaign hinges on retaining those who voted him into government in 2016 as well as expanding the electorate by turning out people who did not vote at the time.

But although his approval ratings among Republicans remain robust, he has no new promises for the voters he is asking to re-elect him for four more years.

Mr Trump’s engagement on Twitter has also dwindled, from an average of 5.37 likes per 1,000 followers at the start of his presidency to 1.29 in February, according to analysis by data analytics company Factba.se.

His engagement numbers fall short of top Democratic presidential contenders Joe Biden and Bernie Sanders, both of whom have just a fraction of Mr Trump’s 25 million-strong Twitter following.

Mr Biden tallied at 2.13 likes per 1,000 followers, while Mr Sanders topped that with 2.73 last month.