A London clinic has accidentally released the HIV status of hundreds of patients

A London sexual health clinic has accidentally leaked the HIV status of 780 of its patients.

On Tuesday, 56 Dean Street sent out an email to all subscribers to its Option E email service - a service intended specifically for those diagnosed with HIV. But because of the way the email was sent - recipients were included in the "To" field rather than the "Bcc" field - every subscriber to the newsletter was able to see the names and email addresses of every other subscriber.

According to Beyond Positive, a news site for people with HIV, 56 Dean Street followed this up with a second email attempting to recall it using Outlook's recall feature - revealing the email list's recipients a second time. An hour and a half later, the clinic sent a third email apologising.

"This is completely unacceptable," wrote Dr Alan McOwan. "We are urgently investigating how this has happened and I promise you that we will take steps to ensure it never happens again."

56 Dean Street is one of the country's leading sexual health clinics, and has won multiple awards, according to its website.

The Information Commissioner's Office is likely to investigate the mistake, and The Guardian reports that it can issue fines of up to £500,000 "for significant data breaches."

NHS England did not immediately respond to a request for comment from Business Insider. Chelsea and Westminster NHS Foundation Trust provided Beyond Positive with the following statement:

We can confirm that due to an administrative error, a newsletter about services at 56 Dean Street was sent to an email group rather than individual recipients. We have immediately contacted all the email recipients to inform them of the error and apologise. Any concerned patients can call 020 3315 9555 and 020 3315 9594 (open until 6pm tonight).

Alternatively patients can ring the Telephone Clinic on 020 3315 9500

Tuesday 5-7pm
Wednesday 2-4pm
Thursday 9-11am
Friday 9-11am

Here's the email sent by Dr Alan McOwan apologising for the error, via Beyond Positive: