'Frustrated' patients have complained of having their appointments on bank holiday Monday rescheduled as the NHS marks the Queen's funeral.
Hospitals and GP surgeries have been making changes to their services planned for Monday September 19, with administrators now being urged to contact all patients to clarify whether or not their appointments have been postponed.
Decisions on whether to provide appointments on the historic day of mourning are being left at the discretion of local hospital trusts.
Urgent and emergency procedures will reportedly be going ahead as normal across the country, while some trusts have said they will postpone non-urgent appointments.
One such body rescheduling non-urgent services is Bedfordshire Hospitals NHS Foundation Trust, who said they would contact all "relevant patients" to confirm but reiterated both their hospitals (Bedford, and the Luton and Dunstable) would still be open for emergency care.
NHS officials in North East Essex and Suffolk meanwhile said GP practices would be closed on September 19 to mark the funeral, with scheduled appointments changed to a later date.
Anyone expecting repeat prescription medicine has also been encouraged to "check you will have enough to last."
Bedfordshire Hospitals NHS Foundation Trust and Bolton NHS Foundation Trust also revealed that changes would be made to appointments due to the bank holiday.
Some patients have been left irritated by the short-notice changes to their appointments. Jo, 30, from Norwich, who did not give her surname, said she felt "incredibly frustrated" after an appointment she had "waited a few months for" was cancelled.
She told the PA news agency: "I get the passing of a monarch is huge for the UK. I'm not a monarchist but I wouldn't want to stand in the way of anyone who feels the need to mourn or pay their respects.
"(The) thing is, I don't think the same courtesy is being paid to people who, for whatever reason, don't want to take part in this proposed period of mourning - or those who do, but who can't afford the financial/health etc implications that seem to be cropping up with all these cancellations of events, appointments and services like foodbanks."
After asking trusts at the weekend to ensure that patients are kept up to date with any changes, a letter sent by NHS England officials on Monday told health leaders to ensure there was "sufficient" out-of-hours cover when GPs close on Monday.
Commenting on the situation regarding provision of services, a spokesperson for the NHS in England said: "As with any bank holiday, NHS staff will work to ensure that urgent and emergency services, including urgent dental and GP appointments, are available - and patients will be contacted by their local trusts, if necessary, regarding their existing appointments.
"Covid vaccination services, particularly in care homes, are being asked to continue their work given the importance of protecting people ahead of winter and the public should access NHS services in the usual way, including through 111 online or 999 in an emergency."
