A former Tory MP has said he will step down at the next general election after being found guilty of racially abusing an activist. Bob Stewart, who surrendered the Tory whip and now sits as an independent in Beckenham, south London, was found guilty of telling Sayed Ahmed Alwadaei to “go back to Bahrain” during a confrontation in central London in December last year. The politician also told the activist “you’re taking money off my country, go away” outside the Foreign Office’s Lancaster House in Westminster. Stewart said in a tweet that it had been “an honour and a privilege” to serve as a constituency MP. The 74-year-old said: “I am incredibly grateful to everyone who has given me this opportunity. However, it is time for a new candidate, so I will not be seeking re-election at the next election.” The prime minister, Rishi Sunak, is not expected to call a general election until autumn 2024 – with 31 October mooted as a potential polling day by some Conservative sources. Stewart had been attending an event hosted by the Bahraini embassy on 14 December 2022 when Alwadaei shouted: “Bob Stewart, for how much did you sell yourself to the Bahraini regime?” During a fractious exchange, Stewart replied: “Go away, I hate you. You make a lot of fuss. Go back to Bahrain.” Last December, the Guardian revealed that Alwadaei complained to the Conservative party about the confrontation outside the reception. The Metropolitan police launched an investigation after a complaint was lodged by the Bahrain Institute for Rights and Democracy activist, who has said he is living in exile after being tortured in the Gulf state. In footage of the incident played during a trial at Westminster magistrates court, the MP is heard telling Alwadaei: “Now shut up, you stupid man.” The chief magistrate Paul Goldspring found the MP guilty of a racially aggravated public order offence. He said Stewart would not be jailed but fined the MP £600, with additional legal costs bringing the total to £1,435. During the hearing, Stewart, a former British army officer who was stationed in Bahrain in 1969, was asked for his thoughts on the allegations of racial hostility. He told the court: “That’s absurd. It’s totally unfair. My life has been … I don’t want to say destroyed, but I am deeply hurt at having to appear in a court like this.” It is understood he could appeal against the verdict.