In November 2010 Circle was announced as the recommended bidder for the Trust's operating franchise.
The franchisee will be required to continue to deliver the services that are currently provided at the hospital.
Hinchingbrooke will remain an NHS hospital, its buildings and assets will remain in the NHS and Hinchingbrooke staff will continue to be employed by the NHS, retaining their NHS terms and conditions.
But in a leaked document reveled to HR, a letter circulated to staff from the hospital, said: "[There is a] slight legal risk that a law called "TUPE" ('the Transfer of Undertakings (Protection of Employment) Regulations 2006') could apply on the commencement of the franchise and, if this were to be the case, the slight risk that unless you formally object, your employment could, under TUPE, transfer to Circle.
"If this happened, it would mean that Circle would become your employer and even though the majority of your terms and conditions would remain the same, you would lose your membership of the NHS pension scheme."
It continued: "There is a commitment that all Hinchingbrooke staff remain employees of the Trust and a part of the NHS. There is, however, a slight legal risk that because of… TUPE, Trust staff could end up becoming employed by the franchisee.
"We do not however believe that TUPE applies in this situation as Hinchingbrooke Health Care NHS Trust will continue to exist and be the employer of staff. However, because the HNS Project is innovative and new, we cannot know for certain.
"Neither Staff Side nor the Trust want you to become employed by the franchisee. To ensure that staff remain within NHS employment in case TUPE should be deemed to apply we will be using he Retention of Employment (ROE) model here at Hinchingbrooke.
"This will enable staff to guarantee they remain as part of the NHS keeping all their NHS terms and conditions of employment (including pension and the right to participate in future negotiations in relation to changes to Nationally agreed terms and conditions)."
ROE is a procedure designed to ensure staff do not transfer out of the NHS.
ROE works because TUPE allows employees to opt out of a transfer - essentially saying that they do not want their employment to move out of the NHS.
Following completion of the ROE process the employer told staff the benefits provided to an NHS employee (including pension rights) will remain the same.
Staff have been asked to sign a 'Notice of Objection to Transfer' letter which confirms they are opting out of the transfer and will be re-engaged by the Trust on existing terms and conditions to take effect immediately after the operating franchise commences.
The letter added: "Neither Circle nor the Trust believes that TUPE will apply to the commencement of the franchise. The arrangements negotiated between the Trust and Circle are based on the assumption that TUPE will not apply.
"As a result the Trust will continue to treat all employees as continuing to be employed by the Trust. However, because of the innovative nature of the HNS Project, we cannot guarantee that TUPE does not apply. So if you do not wish to sign the papers, and TUPE is, at some point in the future, held to have applied, then your employment will be deemed to have transferred to Circle at service commencement date.
"Accordingly, your membership of the NHS Pension Scheme will also be deemed to have terminated on that date.
"We want our staff to remain employed by the Trust on the Trust's Terms and Conditions and in the NHS Pension Scheme. Offering staff the opportunity to opt out of any possible TUPE transfer in this way is the most effective way to guarantee that."
Trade union Unite, said that 'flesh was being put on the bones' of the privatisation of the NHS, and staff at the hospital might face redundancy within the year.
Unite national officer for health, Rachael Maskell said: "For the last 18 months, the government has been actively gearing up to privatise the NHS - and now at the first opportunity they have done so. They are putting the flesh on the privatisation bones.
"Local people in the Huntingdon area will be horrified that their local, acute hospital has now been privatised.
"We predict that in 12 months time, services will decline and some hospital staff will have been made redundant or will be facing redundancy. Circle is a profit-making firm whose first priority is shareholder satisfaction, and not patient care.
"Privatisation, which is central to the Health and Social Care Bill, currently before Parliament, has taken a giant leap forward with today's Hinchingbrooke decision."
Christina McAnea, Unison's head of health, added:"Circle has the same dangerous funding set up as Southern Cross, where it leases buildings owned by companies in tax havens, rather than owning them. The company is losing contracts and millions of pounds in turnover.
"Circle made losses of over £27 million last year and recently floated on the stock market - they look less and less like the social enterprise they claim to be. Their management band is stuffed full of bankers and managers from private industry, who have no experience of health care. Yet this is a company now responsible for the lives of hundreds of thousands of patients.
"We have huge concerns that jobs will be affected by the move, as staffing is the biggest cost area for Trusts. The company is pushing the line that staff are getting involved, while avoiding the fact that merchant bankers are the one calling the shots. It is forging ahead with plans to make a profit when it is not a profitable company in the first place - and has been predicted to have an overspend this year."
Circle, which is part-listed on the Stock Exchange, will take over the running of the hospital in February 2012.
Unite pointed out that this is a growing trend. In September, the Virgin-backed Assura Medical was announced as the preferred bidder to take-over Surrey Community Health in a £450 million deal.
