More than a dozen patients with suspected breast cancer were not seen on time at Barts Health in December, figures show.

Charity Breast Cancer Now said the "frightening consequence" of such vital targets being missed across England was that more women could be living with the disease without knowing.

NHS England data shows 653 patients with suspected breast cancer were referred by GPs for urgent investigations at Barts Health NHS Trust in December.

Of these, 635 (97%) were seen by a consultant within the recommended two-week window – down from 98% in December 2019.

But it was above the national NHS target for 93% of all cancer patients to be seen within this timeframe.

Across England, the proportion of patients seen within a fortnight fell from 90% in December 2019 to just 71% in December last year – the lowest figure for any month since records began in 2009.

Breast Cancer Now said the latest figures were "deeply worrying" and encouraged women to contact their GP if they find any new or unusual breast changes.

Baroness Delyth Morgan, chief executive of the charity, said: “Facing longer waits at an already incredibly difficult time can cause women huge anxiety, and the frightening consequence of these vital targets being missed is that more women could be living with undetected breast cancer due to delayed diagnoses.

"This issue has to be addressed as early diagnosis is key to giving treatment the best chance of success."

NHS figures show just two-thirds of patients with breast cancer symptoms (when cancer was not initially suspected) were seen within two weeks in December – also a record low.

At Barts Health, 203 such patients were referred by GPs in December, with 198 seen within two weeks.

At 98%, this was up from 95% the same month the previous year.

Baroness Morgan added: “At the end of a gruelling year, and still now, we know the diagnostic and imaging cancer workforce is working tirelessly under immense pressure, having already been chronically under-resourced pre-pandemic.

"This is why we urgently need the Government to make the long-term investment and take the strategic approach needed to address the profound scale of the crisis currently facing the cancer workforce."

An NHS spokeswoman said hospitals carried out more than two cancer procedures for every coronavirus patient they treated in 2020.

She added: “These figures show people should come forward if they have a worrying symptom because the NHS has, even at the highest point of the second wave of the pandemic, maintained capacity to carry out cancer checks and support people to start treatment.”

A Department for Health and Social Care spokesman said cancer diagnosis and treatment has remained a priority throughout the pandemic, with £150 million provided in October to allow the NHS to expand diagnostic capacity.