St John Ambulance volunteers attempt to resuscitate athlete during Peterborough's Great Eastern Run

The man is believed to have collapsed after just crossing the finishing line of the half-marathon. Eyewitnesses saw him being given oxygen and CPR.

There has been no official word yet on the man’s current condition.

A Peterborough City Council spokeswoman said a person was taken to hospital during the race and that other runners were treated on-site.

Moreover, it has been reported that a person was struck by a vehicle during today’s race.

The Peterborough Telegraph has also received reports of vehicles driving through roadblocks, including at the roundabout of Park Road, Dogsthorpe Road and Alexandra Road.

Nobody from Cambridgeshire police has yet been available for comment, but the Peterborough Police Twitter account tweeted earlier today: “Great Eastern Run - South bound of Fulbridge Road remains closed. We are receiving calls/complaints re vehicles driving on the closed roads amongst runners therefore Police are having to deploy.”

Superintendent Andy Gipp, area commander for Peterborough and Fenland, tweeted: “Resources are aware of an issue on the ground where there has been a breach and are dealing with it, no ongoing safety issues with that, event commander checking other areas.”