Rail commuters are facing lengthy delays as signal problems force First Capital Connect (FCC) to cancel rush hour services.
Passengers at Huntingdon and St Neots face delays of up to an hour due to a signalling problem between New Barnet and Alexandra Palace.
The 8.21am service from Huntingdon to Peterborough is 59 minutes late, and the 8.49am service to Peterborough has been cancelled.
FCC has also cancelled the 10.34am train to London from Huntingdon as well as delaying most services to the capital.
It is not known when the problem will be resolved.