The boards of three trusts have moved a step closer to creating a single organisation with a turnover of roughly £1.9bn.

Directors at Guy’s and St Thomas’, South London and the Maudsley mental health and King’s College Hospital foundation trusts have agreed to prepare a strategic outline case for a “single, fully-integrated academic healthcare organisation”.

The trusts are already part of King’s Health Partners, one of England’s five academic health science centres, along with King’s College London university.

The move follows a feasibility review by Peter Goldsborough of Boston Consulting Group into whether a full merger between the provider trusts and closer integration with King’s College London was possible.

A document, sent to senior staff and seen by HSJ, said: “We see this as an opportunity to create a new organisation – with room for innovation in organisational form and a strong emphasis on bringing patients and the public closer to the clinicians who plan for and provide their care.”

Based on returns to Monitor, Guy’s had a 2010-11 income of £979.1m, King’s College Hospital of £583.2m and South London and Maudsley of £370m

The involvement of South London and Maudsley means the merger would also be a first in terms of combining acute trusts with a mental health trust.

The document said: “The next step is to create a strategic outline case to assess the benefits, costs, risks and the phasing of the transition path to create this single, fully integrated academic healthcare organisation. In developing the [case] we will engage with a broad set of stakeholders to better understand their issues and concerns to ensure these are addressed in the [case].”

One of the key features of the King’s Health Partners system is its organisation into 21 clinical academic groups covering the different specialisms, a unique structure. Each of the 21 groups integrates care across at least one of the three providers plus training and research with King’s College.

One senior figure associated with the academic health science centre movement told HSJ King’s Health Partners was “taking the AHSC concept further than anyone in England”.

The organisations were keen to stress the merger wasn’t driven by financial pressures, in the way the Barts, Whipps Cross and Newham hospitals merger has been.

Long-term planning documents submitted to Monitor by the three trusts show King’s forecasting an income reduced by £5m by the end of 2013-14, South London and Maudsley predict a £31m drop over the same period.

Guy’s and St Thomas’ predicts an increase in income of £54.7m over that period, compared with 2010-11 out-turn.

William McKee, author of an earlier report into the feasibility of a merger between the trusts last year, said he had seen “considerable” evidence of “passive aggressive behaviour” between the trusts.

His report said: “The waxing and waning of support over two decades for a merger between the two acute trusts is an issue, which in turn has led to defensive and aggressive behaviours.

“An analogy would be a colourful quote ‘land grabs before the armistice’, given to me by a clinical academic group leader.”