Seven areas with high levels of health and social care integration have formally warned the government that its “inflexible” approach to NHS reform will force them to dismantle their current arrangements.

Letters sent last week to health secretary Andrew Lansley and communities secretary Eric Pickles from a group of councils and primary care trusts, including Blackburn with Darwen and Bexley care trusts, argue the areas should be exempt from joining clusters.

The council leaders and PCT chairs say their concerns relate to arrangements for the transition to consortium commissioning and the abolition of PCTs in 2013.

The letters state: “We feel that the seemingly inflexible requirement for a uniform approach to how that resilience [of NHS services during the transition] is to be delivered will produce costly and other unintended negative consequences for the delivery of local public services.”

The council leaders said fully integrated management structures like Herefordshire’s, and integrated commissioning models like those operated between NHS Knowsley and the council, were developed in response to local need and demonstrate “successful localism”.

Herefordshire Council and NHS Herefordshire chief executive Chris Bull told HSJ’s sister title Local Government Chronicle the biggest risk was of sub-regional clustering imposing a one size fits all approach instead of building on existing integrated arrangements.

“What we’re looking for is as much local flexibility as possible and a genuine commitment to allow the transition to be led locally where that is appropriate,” he said.