LONDON — A man accused of driving a van into Muslim worshipers outside a London mosque, killing one person and injuring nine others, was found guilty of murder on Thursday, after a trial that raised questions about the radicalizing influence of far-right groups in Britain.

The man, Darren Osborne, 48, had denied responsibility for the June 2017 assault near the Finsbury Park Mosque, in north London, though he admitted that he had hoped to kill Jeremy Corbyn, leader of the opposition Labour Party, as well as the mayor of London, Sadiq Khan, at a different location.

After an eight-day trial at the Woolwich Crown Court, jurors took an hour to declare him guilty both of murder and attempted murder. He is due to be sentenced on Friday.

The court heard evidence suggesting that Mr. Osborne had been radicalized relatively quickly. According to Mr. Osborne’s partner, Sarah Andrews, his Islamophobic views developed in the weeks before the attack, as he became convinced that not enough was being done to combat Islamic extremism.