Drivers are being advised that the northbound exit slip at Junction 13 for Milton Keynes/Bedford is closed for safety reasons following an issue with an overhead gantry sign.
Engineers need to carry out a visual inspection of the gantry, which would be better off carried out during daylight hours, and require specialist equipment to rectify the cause of the problem.
Traffic travelling northbound who wish to exit the motorway at Milton Keynes/Bedford are advised to continue onto Junction 14 exit and re-join the M1 southbound to exit at Junction 13 on the southbound carriageway.
Road users using the M1 are advised to allow extra journey time and to consider alternative routes if possible.
Highways England provides live traffic information via its website (www.highways.gov.uk/traffic-information), local and national radio travel bulletins, electronic road signs and mobile platforms, such as Android and iPhone apps.