Record delays for a range of medical tests were logged at West Hertfordshire Hospitals Trust in March, as services across the NHS were suspended during the Covid-19 crisis.

That is according to data from NHS England, with trusts providing information on how long people have been waiting for 15 key tests at the end of each month.

The procedures are used to diagnose a wide range of diseases and conditions, including cancers, heart failure, sleep disorders and hearing problems.

According to NHS rules, after someone is referred for one of the tests, they should have it completed within six weeks.

But across England, the number of delays at the end of March shot up to 85,400 – the most for any month since the target was introduced in 2008.

And within West Hertfordshire, 474 patients had been kept longer than the end of March, the data showed.

At 11.1 per cent of those on the waiting list, this was way off the national standard that less than one per cent of patients should wait six weeks or more.

The most common type of test to see delays at the trust in March was echocardiography, which uses high-frequency sound waves that can help spot heart failure – 188 people had been waiting at least six weeks.

This was followed by 114 for an ultrasound, which uses high-frequency sound waves that can detect tumours.

Another 88 people were held up for a DEXA scan, which is used to diagnose bone disorders and related conditions.

West Herts NHS Trust, which runs hospitals in Watford, Borehamwood and St Albans, says staff are doing “all they can” to make sure hospital services return to normal “as soon as it’s safe”.

A spokesperson said: “The staff at West Herts are working very hard to ensure the safety of our patients during these challenging times.

“We are doing all we can to make sure that hospital services, including medical tests, return to normal as soon it’s safely possible to do so.

“Any patients concerned about longer waits for tests should speak to their GPs to see if alternative options are available.”

Nationally, the figures showed 10.2 per cent of people across the country waited longer than six weeks for a test at the end of March, the highest proportion delayed over 12 years.

Dr Jeanette Dickson, president of the Royal College of Radiologists, said the coronavirus will have a heavy impact on certain test waits for the foreseeable future.

“While the NHS will aim to prioritise the patients with the most life-threatening conditions, some with serious illnesses have minor symptoms and so may be missed,” she added.

“Although we cannot give definite numbers, it is likely some patients with cancer may have growth of their disease while waiting for a scan, potentially losing their chance of a cure."

Rachel Power, chief executive of the Patients Association, said people were facing longer waits for tests before Covid-19.

She added: “Rising demand, and increased waiting times are patterns seen in other areas of the health service over the last decade, after a sustained period in which the NHS was underfunded relative to the well predicted growth in patient need.”

NHS England recently announced plans for hospitals to increase routine operations and procedures.

But a group of 16 unions has said rapid testing, and ample supply of protective kit are among measures that must be in place for the NHS to be reopened safely.