[3] The company was founded in 2004 and rebranded as Circle Health Group in 2019 after acquiring a rival, BMI Healthcare; in the same year it began an expansion in China.

[6][7] Circle was founded in 2004 as Centres Of Clinical Excellence Limited,[8] co-founded in 2004 by Babylon Health founder and former investment banker Ali Parsa and consultant ophthalmologist Massoud Fouladi.

[10] In January 2010, Gordon Brown, as Prime Minister, said: "Circle's provision of healthcare from the private sector is crucial to a 21st century health service.

"[11] The company's plans were ambitious, involving opening 30 private hospitals,[12] and encompassing the possibility of running 30 NHS trusts in time.

[16] In October 2015, Circle entered an agreement with Advanced Oncotherapy to open a proton beam therapy cancer centre on Harley Street, London.

[29] In December 2013, the company secured £25M of new funding and overhauled its corporate structure to grant its employees and NHS staff working at its sites direct access to its publicly traded shares.

[32] Circle reported that "the underlying performance of the group improved considerably during 2018", making an EBITDAR profit of £12.3M, up from £6.7M the year before, although the company had an overall loss of £11M as a result of "exceptional costs ... relating to the impairment of intangible assets and goodwill".

[33] In December 2019, the company acquired its larger rival BMI Healthcare to form the biggest private hospital provider in the UK, which it rebranded as Circle Health Group.

As part of the acquisition, American healthcare company Centene (through its subsidiary MH Services) took a 40% stake in Circle Health Holdings.

[37] In August 2023, it was reported that Circle Health Group would be acquired by PureHealth, an Abu Dhabi-based holding company and healthcare platform, in a deal valued at $1.2 billion.

[43] Speaking at Hinchingbrooke hospital, Francis Maude, the Cabinet Office Minister, described the Circle model as "a third option which goes beyond the monopoly of state provision or the private sector".

[44] The journalist Nigel Hawkes' description of Circle as "a John Lewis-style social enterprise co-owned by its employees" was described by Prof Martin McKee as nonsense.

[48] In 2017, Circle Bath received a rating of Good from the CQC,[49] and won a Wylde IA Happiest Workplace in the South West competition.

[27] This was opened as the largest independent sector treatment centre in Britain, as part of a programme of reforms to the NHS which aimed at introducing choice by increasing the diversification of providers.

In 2010, the centre was visited by Andrew Lansley, who said: "The fundamental thing is, is it providing a good care to patients on the basis of NHS principles?

[57] Circle's contract was renewed but the dermatology services were redesigned by Rushcliffe Clinical Commissioning Group, on behalf of all the Nottinghamshire commissioners, "based on its own specification".

[57] In December 2014, it was announced that six of the eight consultants had left rather than transfer to Circle, while recruitment and retention was a problem for NHS hospitals across the East Midlands.

[57] In 2015, the operation of dermatology services during the period in which they were run by Circle Health was described as an "unmitigated disaster" in an independent report commissioned by the CCG and undertaken by Dr Chris Clough of Kings College Hospital, London.

Dr Stephen Dunn, director of policy and strategy at NHS Midlands and East, described it as "a good solution, focused on local needs."

In an opinion piece for The Guardian, he said that "Without this deal, services might have been cut, the hospital might have had to close, or an £80M subsidy might have been needed to support the existing management.

[69] The Prime Minister's former special advisor on health commented in the Daily Telegraph that these results, along with improved care and reduced waiting times, had shown "the right kind of reform can turn around shoddy government monopolies and transform them into huge success stories".

The NAO found that while NHS East of England had assessed bidders' savings proposals, the relative risks had not been fully considered, which had the potential to encourage over-optimistic bids.

[80][81] The hospital made an offer in September 2014 to pay local GPs a £50 'administrative fee' for surgery referrals in an email, signed by Hinchingbrooke chief executive Hisham Abdel-Rahman, which was rapidly withdrawn when the company was accused of bribery.

[87] Later the same day, the CQC recommended the trust be placed into special measures after it was rated "inadequate" on the questions of whether it was caring, safe and well led.