Thousands of NHS operations and appointments are being cancelled and rescheduled as a result of Wednesday's strike, the Government has confirmed.

In England, around 60,000 non-urgent operations, out-patient appointments, tests and follow-up appointments are thought to be postponed. This is based on the NHS doing 20% less work if around a fifth of staff go on strike.

In Scotland, at least 3,000 operations and thousands more hospital appointments are being rescheduled.

Patients have been sent letters warning them of the disruption. Hospitals say emergency and critical care will be unaffected.

The Department of Health in England said it was expecting at least 5,500 non-emergency procedures to be rearranged.

More than 12,000 patients are likely to have diagnostic tests postponed, and 40,000 outpatient appointments are expected to be rescheduled.

On an average day, 28,000 patients have planned treatments or operations in England and there are 60,000 diagnostic tests.

Across the UK, the NHS will operate as if it were a weekend or Bank Holiday. The focus will be on emergency and critical care and patients with the highest levels of need such as chemotherapy and kidney dialysis.

Calls to 999 will still be responded to, but ambulance staff will undertake fewer duties such as transporting patients to hospital.

Figures suggest around 400,000 nurses and healthcare assistants, paramedics, physiotherapists, and support staff like cleaners and administrators, will join the action against changes to public sector pensions.