Smart Motorway gantry sign
A gantry structure spanning the motorway with electronic signals, blue signs showing an exit and the following text.
Exit destinations: A5 Aylesbury (A505) Dunstable (N).
Forward destinations: The NORTH, Bedford, Milton Keynes M1.
Junction number: 11A.
This is a relatively new junction, currently linking to a new road across the top end of Dunstable heading west to the A5. A space has clearly been left for it to go east from here, across the top of Luton to the A505, bypassing both towns, but there's no sign of that being built yet.