London mayor Sir Sadiq Khan has been informally advising Zohran Mamdani, the left-wing Democratic candidate for New York City mayor, on strategies to secure victory in the upcoming November election.

The advice reflects Khan’s own political journey and the challenges Mamdani faces ahead of the general election as reported by the Times.

Mamdani, 33, stunned US political pundits last month when he defeated former New York governor Andrew Cuomo to clinch the Democratic nomination.

Since then, sources confirm, Khan and Mamdani have exchanged texts and spoken by phone, with Khan’s advisers also liaising with Mamdani’s campaign team.

A source close to Khan described the conversation as “warm and collegial,” during which Khan shared words of advice rooted in his experience as a Muslim mayor winning a major Western city’s top job.

According to the report, the central advice from Khan to Mamdani has been to moderate his stance and move towards the political centre to broaden his appeal. This is particularly critical given that Cuomo and the incumbent mayor, Eric Adams, will be running as independents, likely to split the vote in the November 4 election.

A London City Hall insider said, “The primary race is very different from the mayoral election. He needs to moderate or he could lose the more centrist Democrats.”

Mamdani’s mayoral run recalls Khan’s own path to power. In 2016, Khan won the Labour nomination by appealing to the left but subsequently moved to a more centrist position to defeat Conservative Zac Goldsmith in the general election. Khan has since secured two re-elections, applying a strategy of balancing progressive appeal with broader voter concerns.

The Indian Americans campaign champions policies such as opening government owned supermarkets, instituting wide rent freezes, and significantly raising taxes on businesses and wealthy residents, including a pledge to shift the tax burden towards “richer, whiter neighbourhoods.”

These proposals have fuelled criticism, particularly from Republicans and business leaders. US president Donald Trump has branded Mamdani a “communist lunatic” on social media and vowed to block his policies if he wins. Trump posted on his Truth Social platform: “Rest assured, I hold all the levers, and have all the cards. I’ll save New York City, and make it ‘hot’ and ‘great’ again.”

Mamdani, a New York state assembly member and son of Indian Ugandan intellectual Mahmood Mamdani and filmmaker Mira Nair, has energised younger and progressive voters through his outspoken stance on racism, policing, and economic inequality.

His left-wing positions include support for free universal childcare and heavy taxes on residents earning over $1 million a year. At the same time, his critics question his impact on New York’s economic reputation and warn of alienating more moderate voters.

The election has been fraught with intense Islamophobic and right-wing backlash. Mamdani, the first Muslim Democratic mayoral nominee in New York’s history, has faced accusations by Trump loyalists and right-wing figures painting him as radical and dangerous. Some opponents have used anti-Muslim rhetoric to attack his candidacy.

His supporters, however, view his campaign as a blueprint for revitalising centre-left politics, urging others to “ditch pollsters, listen to your neighbours and get back into the damn streets.”