Barking, Havering and Redbridge University Hospitals NHS Trust (BHRUT) faced fines of up to £18,000 last year for breaking rules which ban mixed-sex wards.

NHS England guidance says trusts are expected to have a "zero-tolerance" approach towards mixed sex accommodation, which it says is essential for ensuring safety, privacy and dignity for patients.

It did, however, add that enforcement of the fines is left to individual clinical commissioning groups (CCGs), which plan and buy healthcare from trusts, who could potentially decide to waive them.

In the 12 months to August 2019, BHRUT recorded 72 breaches of the mixed-sex accommodation rules, according to NHS figures.

That was an increase on the 20 instances recorded in the previous 12-month period.

NHS trusts are supposed to be fined £250 per patient each time they break the rules.

This would mean BHRUT faced fines of £18,000 over the course of the year.

The figures do not include instances where mixed accommodation is considered justified, such as in intensive care.

Lucy Watson, chair of the Patient's Association charity, said failing to follow the rules could cause additional anxiety for people already worried about being in hospital.

"We are very concerned that so many people are still being placed in inappropriate hospital accommodation, many years after mixed-sex wards were supposedly abolished," she said.

"Patients deserve to be treated with dignity, and at a time when many will be feeling frail or vulnerable, it is vital that they feel some sense of privacy and safety.

"Patients shouldn't find themselves in a bed next to a member of the opposite sex, particularly if they need to use a bedpan, or have intimate care."

The ban applies to sleeping accommodation, which includes any area where patients are admitted on beds or trolleys even if they do not stay overnight.

Kathryn Halford OBE, chief nurse and BHRUT deputy chief executive said: "Patient care is our number one priority and every decision we make is based on our patients' best interests and safety.

"These breaches usually occur when there are unavoidable delays in moving patients from our intensive and critical care services to wards as their health improves.

"They are the result of the ever-increasing patient numbers we are seeing and demand for beds.

"Sometimes, we determine that keeping a patient close and accessible to a particular specialist medical team is in their best interests.

"While 72 is not a large number - we are well under the national average and it represents just 0.3per cent of the many thousands of patients we see - we take this very seriously and are looking very closely at how we can improve."

Across England, more than 19,900 breaches were recorded over the same 12-month period, a 4.5per cent increase on the previous year.

A spokeswoman for NHS England said: "The vast majority of trusts have completely eliminated breaches and at an average of just 0.7% they remain extremely rare in the context of the hundreds of thousands of people who are admitted to hospital every month.

"But the ambition remains to keep the number of times that this happens to an absolute minimum."