An online tool that claimed to be able to use NHS patient hospital records to reveal treatment "right from initial diagnosis until the current day" has been pulled from the internet after privacy campaigners warned it could be used to identify the precise details of medical care for people in the public eye.

OmegaSolver, a company founded last year, had access to NHS hospital episode statistics and offered an "internal database [which] tracks actual patients within every hospital within England providing … up-to-date information for every disease area". The company said its clients included drugs firms.

However, the firm's website was closed down last week after press inquiries to the health authorities regarding the release of "patient-level" data to the company.

On Sunday it had emerged that a billion NHS patient records have been sold to a subsidiary of Chime Communications, one of the country's biggest PR and marketing firms, which had been working with the pharmaceutical industry.

These revelations will put pressure on to the Health and Social Care Information Centre (HSCIC), the arm's-length body set up to house all of England's patient records, which says it will release within a fortnight the full list of companies, government agencies and charities that have been handed medical data.

Privacy campaigners said that if the OmegaSolver online tool's claims were correct then the medical histories of those in public life could easily be tracked. Phil Booth of MedConfidential pointed out the date when the Labour leader, Ed Miliband, had surgery on his nose to deal with a sleep condition and the hospital where the operation took place were in the "public domain".

"It looks like anyone with access [to the online tool] could pinpoint and read off the medical histories of prominent political figures or pretty much anyone who's had an accident or medical procedure reported in the press or online. Nick Clegg's wife's broken elbow, Tony Blair's catheter ablation, Ed Miliband's nose operation – all reported in the media, providing enough information to spot one event and then read across their every hospital visit. Ministers and officials claim your data will be anonymous, but it isn't."

In response the company said that its Patient Analyser tool, which seemed to track individual patients, was an "illustrative example only".

It added: "Privacy of the individual is one of the basic principles which underpins the terms and conditions governing access to this data, and OmegaSolver takes its commitment to preserving patient confidentiality very seriously. Measures are in place to make sure that the identity of a patient is never discovered. OmegaSolver has access to data items and analysis and makes these available for grouping and linkage purposes only."

The HSCIC said the company had taken down its website. In a statement the centre said: "We have been in contact with OmegaSolver and, while discussions are ongoing, they have assured us that the screengrab provided shows aggregated patient data and does not represent the experience of an individual."

However, the information centre came under fire from MPs on the powerful health select committee over its apparent reluctance to take action.

Barbara Keeley, a Labour member of the committee, said: "We have seen examples of organisations selling applications which link and then display detailed information about individual patients. It is clear that this data could be linked with other information about that person meaning the state of their health could then be tracked."

"Examples have been given of politicians and their family members who received publicity when they had an accident or an operation and were treated in the NHS. If media or social media reports on them can be linked with hospital patient data to track the state of that person's health, it is of very real concern."

"It is disturbing that patients are still being left in the dark about commercial uses of their confidential health information. I am asking questions of health ministers about commercial re-use licences and whether these will now be revoked and the patient data deleted. I am also asking for audits to be done so that patients can be reassured that their confidential medical information is no longer being commercially exploited."