More than 1.2 million people opted out of NHS GP data-sharing in just one month, following a number of privacy concerns raised by campaign groups and openDemocracy.

Under the proposed scheme, launched in May and officially called the General Practice Data for Planning and Research service, anyone registered with a GP in England could have potentially had their personal health data shared with private companies.

NHS Digital introduced the proposal with little publicity, giving GP patients a short, six-week window to opt out by 1 July. After a public outcry and legal threats from a coalition of civil society organisations, this deadline was initially extended to 1 September, and the scheme has now been put on hold indefinitely, according to a report in The Observer.

The data-sharing process was also initially set up to be irreversible – meaning that if people missed the deadline they could not then subsequently have their personal data deleted from the national database.

More than 23,000 people signed a petition in opposition to the GP data grab on the openDemocracy website alone.

Phil Booth of campaign group medConfidential told The Observer that the public response to the data sharing plan “blew up” exactly as he had predicted.

“People do care about their GP records and their medical confidentiality. And there is a simple straightforward thing that they can do, which is to tell their GP ‘please don’t let my data be used in this way’.”

Statistics show that there was a huge spike in the number of people choosing to keep their medical data private, with as many as 100,000 people per day opting out of the planned new scheme in June of this year.

Thousands more continued to opt out in July, as concerns over the GP data grab gained more publicity, including in an online debate on the controversial plans hosted by openDemocracy.

In a further victory for campaigners, NHS Digital has pledged to allow GP patients to opt out of any new data-sharing arrangements at any time.

The government agency is said to be planning to consult on a revised proposal with greater safeguards against inappropriate data sharing.

An NHS Digital spokesperson told The Observer: “We take our responsibility to safeguard data very seriously, and it will only ever be used by organisations that have a legal basis and legitimate need to use it for the benefit of health and care planning and research.

“We have listened to feedback on proposals and will continue working with patients, clinicians, researchers and charities to inform further safeguards, reduce the bureaucratic burden on GPs and step-up communications for GPs and the public ahead of implementing the programme.”

Booth noted that the process of building in safeguards before any relaunch of the scheme would need careful scrutiny, warning that there remained questions about “what’s going on behind closed doors right now in terms of people lobbying against those [concessions] or for particular exceptions to them”.