- ITV News Anglia's Matthew Hudson was at the event
Cambridgeshire Police has revealed that the Great Eastern Run was cancelled over a false alarm.
The half marathon was cancelled after a man was seen acting suspiciously close to the route- on Alexandra Road- leading to a major firearms response.
Cambridgeshire Police say the witness was acting in good faith but 'may have misinterpreted what was seen' adding that it was the right decision to cancel as 'public safety was paramount.'
Around 4,000 runners were taking part, in one of the biggest events in the city.
Organisers have apologised to everyone taking part or watching the event.