Financial challenges, or recurrent/predicted deficits, were cited as the case for merger in 15 of the 20 mergers between 2010-2015 (Collins, 2015). The Department of Health, NHS England and Clinical Commissioning Groups spent nearly £2bn supporting 12 of the 20 mergers (ibid). "There is a consistent trend of overestimating the benefits of mergers and underestimating the time and costs of implementing them, leading to revised calculations and additional funding soon after - and sometimes before - the mergers have been completed" (ibid).
The cost of current and future mergers is likely to be at least equivalent to the cost of earlier mergers. The planned savings from mergers are a fraction of the merger costs. For example, one of the largest mergers, the Barts Health NHS Trust demonstrated that
"…savings of some £238.8m over the next five years are required. Individually the Trusts have only been able to identify around £208.1m of savings. Any further savings made as individual trusts could threaten both the viability and quality of services. The merger gives the Trusts the immediate opportunity to achieve a further £31.8m as a result of cost reductions opportunities made possible by merger synergies" (Barts Health NHS Trust FBC, 2011).
This leaves no flexibility for accommodating the inevitable cost increases.