The London Marathon is considering a radical transformation that could reshape the future of mass-participation road racing. Organisers have proposed expanding the event to a two-day, 100,000-runner format starting in 2027, a move driven by unprecedented demand after the 2026 edition attracted a world record 1,133,813 ballot entries. That figure represents a staggering 36 percent increase on the 840,318 applications received for the 2025 race, underscoring the explosive growth of marathon running's popularity in the United Kingdom and beyond.
The proposal, referred to internally as the "Double London Marathon," would split the field across two days: 50,000 runners on Saturday and another 50,000 on Sunday. One option under active discussion involves moving the professional elite races and a portion of the mass field to Saturday, with the remainder of amateur runners competing on Sunday. Under this scenario, the elite men's and women's races could be held on separate days, giving each event a dedicated spotlight and creating a weekend-long festival of distance running in the capital.
The economic and charitable implications are substantial. Proponents argue the expanded format could raise more than £130 million for charity—nearly doubling the current fundraising total—while delivering a significant boost to London's economy through increased tourism, hospitality spending, and media exposure. The mayor's office has indicated support for the proposals, with a spokesperson confirming the Mayor looks forward to working with London Marathon Events and partners to explore the feasibility of hosting a two-day event.
Not everyone is convinced, however. Critics have raised concerns about the logistical complexity of closing central London's roads for an entire weekend, the potential impact on local residents and businesses, and the risk of diluting the race's iconic single-day identity. There are also questions about whether doubling the field could undermine the exclusivity and prestige that make a London Marathon place so coveted. The tension between accessibility and aspiration is at the heart of the debate, and organisers will need to navigate these competing interests carefully.
For now, the 2026 London Marathon will proceed as a single-day event on April 26, with Emile Cairess, Joshua Sawe, and Benson Kiplimo among the headline names in the elite fields. But the two-day proposal signals a broader shift in how major marathons are thinking about growth, participation, and the evolving relationship between elite racing and the mass-participation movement. Whatever London decides, the rest of the marathon world will be watching closely.