A Republican senator appeared to fall asleep for 15 minutes during Donald Trump’s impeachment trial — while others were spotted doodling, reading books and playing with fidget spinners.

Jim Risch, representing Idaho, sat slumped with his eyes closed and his head resting on his right hand as the charges against the US president were outlined.

While independent cameras are not allowed to film proceedings, a sketch artist recorded the alleged doze at around 5.30pm on Thursday.

Reporters also claimed Republican Senate leader Mitch McConnell and Democrat Kirsten Gillibrand also briefly fell asleep before jolting back awake in their seats.

Senators are only allowed to drink water or milk inside the chamber and are banned from talking to each other, eating snacks or using their phones or computers.

The restrictions prompted Texas Republican Ted Cruz to devise an impeachment drinking game: “Every time House Dems say ‘drug deal’ or ‘get over it’... drink a shot of milk!”

All the president's lawyers: The team fighting Trump's impeachment Show all 6 1 /6 All the president's lawyers: The team fighting Trump's impeachment All the president's lawyers: The team fighting Trump's impeachment Alan Dershowitz Dershowitz is a controversial American lawyer best known for the high-profile clients he has successfully defended. Those clients have included OJ Simpson, Jeffrey Epstein and Harvey Weinstein. One longtime Harvard Law associated told the New Yorker Dershowitz "revels in taking positions that ultimately are not just controversial but pretty close to indefensible." Getty All the president's lawyers: The team fighting Trump's impeachment Ken Starr Starr became a household name in the 1990s as the independent counsel who led the investigation that led to Bill Clinton's impeachment. That investigation began as a look into a real estate scandal known as Whitewater, and eventually led to impeachment after Mr Clinton lied under oath about having an affair with White House intern Monica Lewinsky. AP All the president's lawyers: The team fighting Trump's impeachment Jay Sekulow Sekulow is the president's longtime personal attorney, and, now, personal lawyer in the White House. He has been accused by former Rudy Giuliani associate Lev Parnas of being "in the loop" during the Ukraine scandal. Getty All the president's lawyers: The team fighting Trump's impeachment Pam Bondi Bondi is the former attorney general in Florida, and a longtime backer of the president's. She made a name for herself in Florida for taking hyper partisan stances on issues, and her penchant for publicity. She is likely to be a prominent public-facing figure during the trial. AFP/Getty All the president's lawyers: The team fighting Trump's impeachment Pat Cipollone Cipollone is the White House counsel, and leading the president's defence team. Getty All the president's lawyers: The team fighting Trump's impeachment Rudy Giuliani While not officially named as one of the president's impeachment lawyers, it is hard to ignore Giuliani's outsized role in this process. The former mayor of New York has been making headlines for months as he defends his client, and for his apparent role in the effort to compel Ukraine to launch the investigation into Joe Biden. We'll see how he figures in the actual trial, which he has said he would like to be a part of. Reuters

And Richard Burr, the Republican representative for North Carolina, handed out fidget spinners — a toy designed to relieve stress or boredom — to his colleagues at the start of the third day of trial.

He was later seen playing with a blue spinner while House impeachment manager Jerrold Nadler made his speech.

Tennessee Republican Marsha Blackburn admitted reading the book Resistance (At All Costs): How Trump Haters Are Breaking America by Kim Strassel during the hearing.

She claimed it gave her “good insights” into the impeachment proceedings, before adding that “busy mamas are the best at multi-tasking”.

Meanwhile Rand Paul, Republican senator for Kentucky, set about drawing a picture of the US Capitol.

Democrats are due to conclude their arguments on Friday before Mr Trump’s legal team begins its own case on Saturday.

Jay Sekulow, one of the president’s lawyers, said they could take up to three days, adding: “We’re going to use a sufficient amount of time to defend our case and point out the inconsistencies of their case. We’re not going to run out the clock.

“I am confident that whether it is (completed) Saturday or Monday or Tuesday that the case will be made defending the president. I have no doubt.”