A global supply chain issue has led to doctors being told that all clinically necessary tests can go ahead but others will have to be scaled back.

Due to the shortages, NHS England has issued new guidance to GPs urging them to only call for some tests under certain circumstances, as part of a plan to ‘reduce non-essential (non-clinically urgent) testing’.

It means that patients with suspected allergies and vitamin D deficiencies could face delays to routine testing. Fertility tests could also be impacted by the global shortage.

A spokesperson for the Department of Health and Social Care said: "Patient safety and continuity of care is our priority and we are working to ensure there is minimal possible impact on patient care.

"The health and care system is working closely with BD to put mitigations in place to resolve any problems if they arise."