An ex-New York City police officer who assaulted law enforcement officials during the 6 January riots has been sentenced to 10 years in prison.

Thomas Webster, 56, was convicted in May on multiple charges, including assaulting police and violent and disorderly conduct.

More than 850 people have been charged over their involvement in the attack.

But the sentence handed down on Thursday is the longest imposed on anyone over their role in the riots.

A federal jury in New York previously rejected Webster’s argument that he had been acting in self-defence when he swung a metal flagpole at an officer and tackled another to the ground, holding him in a chokehold.

In pre-sentencing documents, the Marine Corps veteran disavowed former President Donald Trump’s claims that the 2020 election was stolen and included a letter of reference from a friend who blamed the Republican politician’s “despicable lies” for inducing Webster’s conduct.

Jurors accepted prosecutors’ argument that Webster had “spearheaded” an attack on police lines and that he was responsible for “disgracing a democracy that he once fought honourably to protect and serve”.

“Notwithstanding his background and training, Webster did not try to de-escalate the situation or leave the premises,” the justice department said in court filings. “Webster spent eight minutes elbowing his way through the densely packed crowd so that he could position himself at the front of the mob.”

The court agreed to suspend the final 36 months of Webster’s term in deference to his 25 years service as a police officer and soldier.

The sentencing comes as US law enforcement officials also detained Kellye SoRelle, a lawyer for the far-right Oath Keepers group.

Ms SoRelle was indicted on four charges in connection with the 6 January attacks, including obstruction of justice.

Several members of the group have pleaded guilty to criminal charges arising from the attack on the Capitol, where a number of Oath Keepers were seen entering the building in military style body armour.

The 43-year-old previously volunteered with Lawyers for Trump during efforts to challenge the 2020 election results.