The Care Quality Commission is advising people to take care when using online primary care services and ensure that they follow guidance set out by the General Medical Council, as some have been found to be putting patients at risk.

The regulator has stressed that its investigations have revealed risks to patients may not always be appropriately assessed or managed when medicines are purchased online.

The call came alongside publication of two reports based on "urgent inspections" of two providers of digital primary care, MD Direct, which subsequently withdrew its registration, and HR Healthcare Ltd, which had its registration suspended by the CQC.

Inspectors found that the two providers "demonstrated significant clinical safety and organisational risk to patients", with "widespread failings to provide safe care".

Among the list of concerns: there were either no or very minimal identity checks carried out on patients; there were no processes in place to allow for contact with the patient's regular GP, including when medication was prescribed that required monitoring or follow-up; and there were no assurances that clinicians had relevant skills or qualifications for the role they were performing.

Anyone selling medicines to the public online must be registered with MHRA and display the common logo. The CQC has completed an internal review of all 43 online services currently registered, and brought forward a programme of inspections prioritising those services it considers as potentially presenting a significant risk to patients.

Eleven inspections have been carried out so far, which have revealed "really serious problems" among providers, reports on which are due to be published in the coming weeks, Professor Steve Field, chief inspector of General Practice at the CQC, told the BBC.

"In some cases we have found websites which in effect allow people to select their own medication, including medicines restricted as prescription only, with little or limited clinical oversight," he said in a CQC release. "Patients can go online, self-diagnose their condition, order their own medicine and obtain a prescription from the online doctor service, with minimal checks on who they say they are and whether the medication is safe or appropriate for them, often within a matter of seconds."

"It's incredibly concerning to hear reports of patients buying prescription drugs online, often from unverified websites, with minimal security checks in place - so it's good to see the CQC and others recognising this, and taking the issue seriously," said Professor Helen Stokes-Lampard, Chair of the Royal College of GPs.

"We would urge our patients to consider the implications of buying drugs online using unverified websites - there is no way of knowing what they are buying is what they think it is, and this can have terrible consequences. Instead, if they think they need medication, we would advise them to seek the help of a healthcare professional, such as a GP or pharmacist, who can advise on the best course of treatment if it's necessary."

Sandra Gidley, Chair of RPS England, also argued that "unless and until the standards for remote prescribing by private providers reflect the standard of face to face consultations in the NHS, that have been used to reduce unnecessary antibiotic prescribing, we cannot support services that increase the inappropriate use of antibiotics".

Four regulatory bodies - CQC, the General Medical Council, the General Pharmaceutical Council, and the Medicines and Healthcare products Regulatory Agency - have now put out a joint statement reminding providers and healthcare professionals working for these services that they must provide safe and effective care, including following professional guidelines.

"We share a joint commitment to ensure that the same safeguards are in place for patients whether they attend a physical consultation with their GP or seek medical advice and treatment online.

"We will continue to work closely together to share intelligence where we have concerns and take action where necessary to protect patients. We will ensure providers and clinicians are clear on their responsibilities to protect people who use their services and deliver safe, high quality care," they said.