Boris Johnson has been spotted looking at schools and is house-hunting in Oxfordshire, prompting speculation he is considering running for his former seat of Henley at the next election, the Guardian has been told. The former prime minister had been planning to contest his existing seat of Uxbridge, a marginal in west London with a majority of 7,200. However, Labour believes it could be winnable and if Johnson loses it could end his hopes of another run at Conservative leader. Johnson’s successor in the leafy Oxfordshire seat, John Howell, is understood to have told local Conservative party members privately that he has not yet made up his mind whether he will run again or stand down at the election, expected next year. The Tory MP declined to comment. While other local Conservatives are already tipped to go for the seat, which has a majority of 14,000, the former prime minister has increased speculation he might be interested in standing after he was seen visiting local schools for his two youngest children. One member of the Henley Conservative association said: “John hasn’t made his mind up yet whether to stand down or stand again but already there’s several candidates lining up to take over. It wouldn’t be at all surprising if Boris decided to throw his hat in the ring.” Several Tories are already said to have made the calculation to go on the “chicken run”, swapping newly marginal seats for true blue constituencies, in the hope of hanging on at the next election. One new seat is being created in Oxfordshire under the boundary review. Johnson still owns a house in Thame, in the Henley constituency he represented from 2001 to 2008, according to the register of MPs’ interests. Sources close to his family have suggested he has been looking at other properties in Oxfordshire. However, allies have denied the claim. A spokesperson for the former prime minister said: “Boris Johnson has already confirmed he will be standing in Uxbridge and South Ruislip at the next election.” Rishi Sunak, the prime minister, has said Johnson intends to stand in Uxbridge, although his majority suggests he is vulnerable to being unseated by Labour. “I think the former prime minister has declared his intention to stand in his current seat in Uxbridge,” Sunak told reporters earlier this month. It followed reports – denied by Downing Street – that the prime minister had struck a deal with Johnson to find him a safe seat in exchange for agreeing not to challenge Sunak after May’s local elections. However, few Tory MPs believe that Johnson, who was ousted last summer over his handling of a series of scandals and still faces a privileges committee inquiry into whether he misled the Commons over Partygate, has the support he would need in the parliamentary party to attempt to force Sunak out. Johnson was witnessed earlier this month being shown around an independent school in Oxfordshire, which the Guardian has chosen not to name, with a view to sending his son Wilf there as a day pupil in September 2024, followed by his daughter Romy. His four children with his ex-wife Marina Wheeler, a barrister, all attended state primary schools in north London.