Network Rail have confirmed that 1,000m of cable has been stolen from the line between Bedford and Bletchley.
A spokesman told ITV Anglia that rail delays would continue for the rest of the day while engineers worked to make repairs.
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A weather warning for strong winds is in force with gusts of 40-50mph. This strength of wind is enough to cause disruption to travel.
Anglia Weather: Mainly dry today, but mild and windy with top temperatures of 16 deg C (61 deg F).
Norwich writer Sarah Hall has been shortlisted for the East Anglian Book Awards with her unsettling short story collection, Madame Zero.