The failed appointments waste time and heap pressure on consultants who already face “extraordinary demand” due to the virus, says the British Medical Association.
NHS Digital data shows that in the 11 months from April last year, there were 18,345 outpatient appointments which people did not show up for at The Shrewsbury and Telford Hospital NHS Trust, which runs Royal Shrewsbury Hospital and Princess Royal Hospital in Telford.
It means out of 462,240 booked sessions, four per cent were unattended.
And with the average outpatient appointment costing £160 – as estimated by several NHS trusts – the no-shows may have cost the trust around £2.9 million.
There were 4,935 outpatient appointments which people didn't show for at the Robert Jones and Agnes Hunt Orthopaedic Hospital Trust, near Oswestry, which could have cost the trust around £790,000.
Meanwhile, Shropshire Community Health NHS Trust (Shropcom) faced losing around £260,000 with 1,625 unattended appointments.
Health bosses have urged people to attend their appointments, or let someone know if they need to cancel.
Stacey Keegan, chief nurse and patient safety officer at RJAH, said: “We would like to advise patients that it is important you attend at the date and time you are offered in your appointment letter.
"If for any reason you find you cannot attend, then please let us know as soon as possible as we may then be able to offer your slot to someone else.
“Over the last 12 months, we have done a large number of appointments over the telephone and virtually but when people need to attend face-to-face appointments, it is safe for them to do so.
“We appreciate that many people may still feel nervous about attending hospital appointments, given the difficulties of the past year. However, we would like to reassure you that every possible precaution is taken to ensure your safety at all times.
“If we can cut the number of missed appointments then that will mean more people are being seen in clinics, and they are being treated faster. Everyone benefits from that – the patients and the hospital.”
Steve Gregory, executive director of nursing and operations at Shropcom, has also moved to reassure patients that its hospitals have Covid safety measures in place.
He said: “We can assure you that every possible step is taken to ensure your safety throughout the pandemic and at all times.
“If you have an appointment, please do attend as planned. If you absolutely cannot make it, then please let us know in good time as that space may be able to be offered to someone else.”
Dr Nikki Kanani, NHS England’s primary care medical director, added: “Everyone should continue to attend their medical appointments – including for screening and immunisations – as there are strict measures in place to keep patients safe.
“If you are unable to attend for any reason, our message is clear, please let us know so your appointment can be filled by another patient who may need it.”
Across England's health providers, five million appointments were missed during the same period to the end of February, around seven per cent of those booked – wasting the NHS an estimated £760 million.
Dr Rob Harwood, BMA consultants committee chairman, said it was “concerning” to see the rate of failed appointments given the current backlog in care.
He said: “We urge people not to just simply fail to attend as this wastes an appointment time that could have been used for someone else; someone who might potentially need it more urgently.
“It also places the most pressure on consultants trying to deliver a service under extraordinary demand and in already difficult circumstances.”