Buckinghamshire should be merged into a combined authority with Oxfordshire and Berkshire as part of plans to broaden devolution across England, a think tank has said.

A new report by the Institute for Government argues for further devolving powers to the home counties and other regions, following commitments by the new Labour government to widen devolution.

The think tank says there is a ‘strong case to be bold and to prioritise’ the creation of a Thames Valley mayoral combined county authority across Oxfordshire, Buckinghamshire and Berkshire.

It recommends negotiations to create a ‘Thames Valley combined county authority’, with or without mayor.

This would be an attempt to give Thames Valley leaders greater control over key economic powers and budgets as has happened under devolution elsewhere in England in places like Manchester and the West Midlands, which have their own metro mayors.

The Institute for Government said the combined Thames Valley authority would have a total population of 2.3 million and an economy of £101.0 billion.

Its report reads: “The greatest disadvantages for this approach are the separate media regions, the lack of alignment to earlier geographic footprints and no current public support from key political figures in the region.

“Indeed, the leader of Oxfordshire County Council has expressed public reservations about any deal that would incorporate Oxfordshire into a larger combined authority.”

The recommendation to group the local authorities into a Thames Valley combined authority is more ambitious than the existing provisional devolution deal that Buckinghamshire is yet to fully agree with Westminster.

Last month, Labour said it would continue with eight provisional devolution deals made by the previous Conservative government, including a non-mayoral devolution arrangement in Buckinghamshire.

The Tories’ devolution deal in principle with Bucks Council, excluding Milton Keynes, was announced in March of this year.

The previous government said at the time: “This agreement marks an important step for devolution in Buckinghamshire by giving local leaders more control and influence over the levers of local growth.

“The agreement transfers new powers and funding to Buckinghamshire Council, including devolution of the adult education budget.”

The provisional deal was made under ‘Level 2’ of the government’s devolution framework, which the Tories said would ‘give local leaders more control and influence over the levers of local growth’.

The responsibilities that would be devolved to Bucks include the adult education budget, which funds education and training for adults aged 19 and over.

One of the other main powers would be that the council would be granted is the ‘local enterprise partnership’ functions, giving the unitary authority a greater say over economic development in the county.

Another part of the provisional deal states that the government and Buckinghamshire would ‘further explore’ the devolution of Homes England land assembly and compulsory purchase powers for housing and regeneration.

Martin Tett, the leader of Bucks Council, told the Bucks Free Press: “Buckinghamshire Council is currently in discussion with central government over a possible Level 2 devolution deal for Buckinghamshire that was agreed in principle by the previous government.

“While these discussions are ongoing, we are not able to disclose any further detail but look forward to progress continuing.”