The astrophysicist, who denied the allegation, had been arrested 15 times during the Covid pandemic
Westminster Magistrates’ Court heard that Mr Corbyn – the defendant – told nursing sister Chelsea Butcher: “We are not leaving, you are murdering people here.”
Prosecutor Iestyn Morgan said Mr Corbyn and David Burridge, 44, from Hounslow, west London, refused to leave the hospital when told to by NHS staff and police.
Mr Corbyn, an astrophysicist and conspiracy theorist from Walworth, in south-east London, said he had been arrested 15 times since the start of the pandemic, and claimed: “We were not there trying to obstruct people doing anything.”
In February, Mr Corbyn denied that he had been “abusive” toward medics and he and Mr Burridge plead not guilty.
Prosecutor Luke Staton had said: “The defendants were somewhat abusive towards members of staff, calling them murderers.”
Interrupting Mr Staton in the courtroom, Mr Corbyn said: “We said nothing. Open lies in open court is unacceptable.”
But the two defendants, who represented themselves at a one-day trial, were on Friday found guilty by District Judge Briony Clarke of causing a nuisance or disturbance on NHS premises without reasonable excuse.
She fined Corbyn £250 and Burridge £200, ordering them to each pay a further £234 in costs and other charges.
“In my view the defendants were there in order to try to stop the centre operating, hence the ‘cease and desist letter’ they were producing to the members of NHS staff,” she said.