Last month, the three English counties of Northamptonshire, Oxfordshire and Buckinghamshire became the latest area to express a wish to form their own combined authority. The counties stated a desire to work collectively to deliver public transport, skills and infrastructure, reflecting the needs of businesses at the scale of the local economy, rather than at that of administrative boundaries.

The announcement reflected the concerns felt by many non-urban areas that they will miss out on the current trend towards devolution. Recent deals for Greater Manchester and Greater Sheffield demonstrate a willingness from the government to devolve control over funding and delivery – of public transport, skills and housing – to big cities if they can demonstrate they are working together.

But beyond the major city regions there is little indication from government whether devolution is on the cards. This reflects the difficulty and complexity of devolving to two-tier areas (those which have both local authorities, and county councils). This is particularly true for those areas that include a city council within a county one.

In many instances, the two-tier system of local government means cities are under-powered. They have little or no formal influence on the economic growth, strategic growth and infrastructure decisions that are so vital to ensuring the city economy functions well.

Oxford, for example drives economic growth and job creation in Oxfordshire – between 25 and 50 per cent of residents of the county work in the city, and its economy is one of the strongest performing in the country. But as a district council, Oxford lacks the tools to ensure that public transport effectively connects people in and around the city with jobs and businesses; or the power to deliver the housing that the growing city economy needs.

Cities like Oxford, Cambridge and Norwich need to work on an equal footing with their economically-linked counties to support economic growth. As part of a two-step model, we propose they gain unitary status, as a precursor to joining their county in combined authority-style arrangements.

Counties are right to capitalise on the benefits of working across administrative boundaries to think about how to deliver the infrastructure, education and training that will support businesses at the scale of the real economy. But in the case of Oxfordshire and Northamptonshire, they need to make sure that Oxford and Northampton have an equal voice at the combined authority table.

This will ensure the decisions made are the right ones – to enable these cities to unlock growth and boost jobs in the wider area.

Louise McGough is a policy officer at the Centre for Cities. This article was first posted on the think tank’s blog.