The patient had been on a ward last week but is not believed to be connected in any way to the first case, a man in his 80s who died at the hospital on Thursday.

This patient is younger and, because there are no serious underlying health problems, is able to self isolate at home.

It is understood he or she has recently returned from a Spanish island, which is not flagged up by the NHS as a coronovirus risk area. But hospital staff decided to carry out a test to "be on the safe side" said a source.

The second swab will confirm the case

"The patient was on a general ward then moved to a side room to be isolated. They were discharged on Friday evening and the test came out positive shortly afterwards. They are waiting for the results of a second swab to confirm it," added the source.

"The problem is that the trust is relying on NHS guidelines about the countries people have travelled to - and that's why neither patients was flagged initially."

The Spanish island visited by the second patient currently has only six cases of confirmed coronavirus.

And the elderly gentleman who passed away had recently returned from a cruise of the Carribean - again an area not considered a risk by the authorities.

Described by his family as a "truly loving and wonderful" husband, dad, granddad and great-granddad" he had presented in A & E on Monday night and was admitted to a ward, where he remained for several hours before he was put in an isolation side room.

On Thursday, he was confirmed to have tested positive for COVID-19, and died shortly afterwards, surrounded by his family.

A statement from Milton Keynes University Hospital said it had followed, and will continue to follow, all national guidance on the identification and management of patients with suspected COVID-19.

It added: "This includes when to test and when to isolate patients as a precaution against the possible spread of infection. Guidance changes week-to-week given the evolving nature of COVID-19 in England, and we keep abreast of all updates.

"We have stringent infection control protocols in place; and are working closely with national agencies, including Public Health England, to ensure we are doing everything possible to safeguard all those using the hospital at all times."

The government's plan for tackling the spread of the virus states that for most people who have it, self-isolation at home will be one of the main ways to control it.