The plans are expected to see the current 42 ICBs merged into around 27 clusters.

ICBs were expected to submit their cluster plans by the end of May with clusters expected to be formed within 12 months.

A blueprint defining ICBs role as strategic commissioners with a strong focus on improving population health, reducing inequalities and ensuring access to high-quality care was published last month.

Guidance has stated geographical boundaries should pay due regard to local government devolution, with local authorities only having one ICB in their area and populations should be no smaller than 1m.

Concerns have been expressed about the speed of change at ICBs, however, with local government leaders having revealed a lack of engagement in the process.

In the South East, the preferred option is to form four ICBs from the current six with Buckinghamshire, Oxfordshire and Berkshire West expected to merge with the Berkshire East population currently served by Frimley ICB as part of the process.

Elsewhere, NHS Herefordshire and Worcestershire ICB has revealed its plans to cluster with NHS Coventry and Warwickshire ICB.

A spokesperson on behalf of NHS Herefordshire and Worcestershire ICB said: ‘We are currently working with NHS Coventry and Warwickshire ICB to explore what these proposed shared management and leadership arrangements could look like. The work to develop new structures over the coming months will be informed by these proposals.'