A laboratory which wrongly gave the all clear to women’s smear tests was still waiting to be accredited by a national standards body at the time, it has emerged.

A total of 2,500 smear tests carried out by the Pathology First lab in Bentalls, Basildon, are being retested after diagnostic errors were made.

The lab tests a range of samples for Southend and Basildon Hospitals. It was launched as a joint venture between the hospitals and private company Integrated Pathology Partnerships (iPP) in 2016.

Pathology First initially received accreditation to carry out gynae-cytology - smear tests - at a lab at Basildon Hospital in 2015.

Tests were then carried out at the new £10million lab in Basildon, which opened in February 2016, and had to be reaccredited by the UK Accreditation Service (UKAS) – the sole national accreditation scheme for the UK.

This was not granted until July last year - more than a year later and a month after the investigation into the smear test errors was launched in June.

Asked if this meant Pathology First did not have accreditation to run tests at the Bentalls lab until July, a UKAS spokesman replied: “That’s correct. Accreditation has been maintained at Basildon University Hospital lab throughout.”

The organisation granted accreditation smear tests on July 28, 2017.

Accredited bodies are assessed by international standards and are regularly tested and inspected. Without accreditation, the organisation could have been at risk of falling short of standards.

The UKAS spokesman added that an Extension to Scope (ETS) needed to be applied for to add the new location.

A Basildon Hospital spokesman said: “The cytology service at Basildon Hospital was given UKAS accreditation in 2015. This service transferred to the Pathology First hub lab in 2016.

“An Extension to Scope assessment visit, reflecting the change to the new laboratory location, was held as timetabled by UKAS in 2016 to accredit the service.

“During this visit, accreditation was granted subject to the clearance of any non-conformities within the UKAS mandated period of three months. This is standard practice and Pathology First received formal confirmation of accreditation in 2017. A further routine surveillance visit was undertaken in October 2017, and formal confirmation of accreditation was received in early 2018.”

UKAS does not apply any sanction to unaccredited bodies but said it would expect NHS England to do so.

NHS England said it was unable to respond.