Revealed: secret plans for two-day London Marathon with 100,000 runners

• ‘Double London Marathon’ plans backed by mayor’s office

• 2027 event would raise tens of millions more for charity

The London Marathon is in advanced talks about staging a two-day event in 2027, allowing tens of thousands more runners to take part in the iconic race and to raise tens of millions more for charity.

While the Double London Marathon, as it is being called internally, has not been granted formal approval it is believed to have the backing of the mayor’s office for it to be staged on Saturday 24 and Sunday 25 April next year.