Pressure is mounting on health officials to add loss of smell and taste to the official list of symptoms for Covid-19 after increasing numbers of people reported they were suffering from both.

ENT UK, the professional membership body representing ear, nose and throat surgery in the UK, published guidance to patients on Wednesday saying it believed anosmia (loss of smell) and loss of taste were symptoms of coronavirus, adding that it had shared these details with Public Health England (PHE).

It said loss of smell following any viral infection is the second most common cause of smell loss generally and therefore it "is therefore perhaps no surprise that the novel Covid-19 virus would also cause anosmia in infected patients."

It added: "There is growing evidence that significant numbers of patients with proven Covid-19 infection have developed anosmia/hyposmia (reduced sense of smell).

"For example, in Germany it is reported that more than two in three confirmed cases have anosmia."

The organisation said ear, nose and throat surgeons across the globe have shared reports of a peak in patients reporting anosmia in the last month.

"We believe this is related to Covid-19 infection," it said.

"At present, many affected patients do not have other symptoms, or only mild disease, and therefore do not meet the criteria for testing.

"While loss of smell may be caused by other viruses, we think that it is reasonable to assume that Covid-19 is the cause until tests prove negative.

"We therefore advise that patients follow current guidelines for self-isolating if they develop new onset anosmia. This will also apply to cohabiting friends or family."

Currently, people in the UK are being told to self-isolate only if they have a persistent cough, or a high temperature, or both, or if somebody in their family does.

This is based on large-scale data from China, where the most common symptoms reported are fever, a dry cough and fatigue.

However, the World Health Organisation (WHO) has said it is investigating the link between loss of smell and taste and Covid-19.

Maria Van Kerkhove, the head of the WHO's emerging diseases and zoonoses unit, said on Monday: "A loss of smell or a loss of taste is something that we're looking into.

"We are reaching out to a number of countries and looking at the cases that have already been reported to see if this is a common feature. We don't have the answer to that yet."

It comes as several small studies have found that some people with Covid-19 experience loss of smell, loss of taste and/or gastrointestinal problems.

Earlier this week the football presenter Gary Lineker's son George said he had suffered a "complete loss of sense of taste and smell".

He tweeted: "Quite a few of you out there who can't smell or taste either. I've had it for a few days but only heard about this being a symptom last night, if i have it. Pretty much been home the past few days but now isolating as it can be contagious. Feel fine & still exercising daily."

Health minister Nadine Dorries also said she lost all sense of taste and smell after testing positive for Covid-19.

Jonathan Ball, professor of molecular biology at the University of Nottingham, told the Daily Telegraph: "Throughout the outbreak I have been incredibly bothered by the (UK's) restricted case definition.

"When you look at the medical reports describing how cases are presenting, particularly mild infections, coronavirus patients clearly have cold-like symptoms."

In the UK, both the NHS 111 coronavirus symptom checker and a new Covid-19 symptom checker app list high temperature, cough and breathlessness as symptoms, with no mention of loss of taste and sense of smell.

PHE has been contacted for comment.

By Jane Kirby, PA