The 13 councils that are part of the discussion are:

Bracknell Forest Council

Cherwell District Council

Oxford City Council

Oxfordshire County Council

Reading Borough Council

Royal Borough of Windsor and Maidenhead

Slough Borough Council

South Oxfordshire District Council

Swindon Borough Council

Vale of White Horse District Council

West Berkshire Council

West Oxfordshire District Council

Wokingham Borough Council.

Five of Oxfordshire’s Lib Dem MPs previously backed the inclusion of Buckinghamshire but the area is not included in the current expression of interest.

Swindon prefers to join the Thames Valley MSA, although it is not in its geographical patch.

Oxford City Council previously said Swindon would make the proposition for a Thames Valley MSA even stronger, while the county council said it made more sense for it to look to the west and south for partners.

The leaders’ letters said that a Thames Valley MSA would be “a strategic platform from which to go further and faster on pan-regional collaboration with our neighbours”, such as the Oxford – Cambridge Corridor.

Council discussions will now continue with development of detailed proposals in the coming months.