Research carried out by Oxford University's Evolutionary Ecology of Infectious Disease group points to the virus possibly being in the UK by mid-January at the latest - a month earlier than previously thought.
The idea is one of a number that researchers believe are possible.
In the non-peer reviewed study they suggest that the coronavirus, like many emerging infections, may have spread invisibly for a month before its effects became clear at the end of last month.
If the Oxford researchers are right, then as much as half of the country's population may already have been infected.
Below are the eight symptoms that may suggest you have already been infected by the coronavirus.
New research has indicated that eye infection such as conjunctivitis may be a symptom of Covid-19.
The College of Optometrists said: "It is recognised that any upper respiratory tract infection may result in viral conjunctivitis as a secondary complication, and this is also the case with Covid-19.
"However, it is unlikely that a person would present with viral conjunctivitis secondary to Covid-19 without other symptoms of fever or a continuous cough as conjunctivitis seems to be a late feature where is has occurred."
A dry cough
Perhaps the most recognisable of the Covid-19 symptoms, given how different it can sound compared to a typical cough.
The cough is generally new for you - or different if you generally have a smoker's cough - and persistant.
More often than not it will last for at least half a day.
Although this has not been officially chalked up as a symptom, Covid-19 sufferers have reported experiencing mental fatigue.
Thea Jourdan told The Daily Mail that she first thought she may have been infected when she got a tickle in her throat and a headache.
The mum-of-three then began to experience brain fog.
"Initially I felt exhausted, as if I was dragging myself through treacle and had no choice but to go to my bed. I had no meaningful cough and I wasn’t running a fever," the Hampshire woman told the publication.
"But I had a peculiar sensation of something settling deep within my lungs, almost like breathing in talcum powder."
A high temperature
Although numbers vary for different people, a rise in body temperature generally counts as a fever once it reaches 37.7C (100F).
You can tell you have a fever if you feel hot to the touch on your chest or back.
It's difficult to catch your breath
If your chest starts to feel tight or you cannot breath, you may have caught the coronavirus.
Most young people or those without pre-existing health conditions are unlikely to experience this symptom.
Dyspnea - the term for when someone has difficulty breathing - may be coupled with a tightness in the chest, rapid breathing and heart palpatations.
Loss of sense of smell and taste
Over the weekend the British Association of Otorhinolaryngology warned that losing your sense of smell and taste may mean you have Covid-19.
The ear, nose and throat specialist recommended anyone with such symptoms self-isolate immediatley.
It has been suggested that the phenomena may be caused by the coronavirus killing cells in the nose and throat.
"Evidence from other countries that the entry point for the coronavirus is often in the eyes, nose and throat areas," the Association said in a statement.
"We have also identified a new symptom (loss of sense of smell and taste) that may mean that people without other symptoms but with just the loss of this sense may have to self-isolate - again to reduce the spread of the virus."
As with a loss of appetite, enduring a tummy ache may easily be passed off as a sign of something more innocuous.
However, a newly published study by the American Journal of Gastroenterology links tummy problems to Covid-19.
They found that 48.5 per cent of 204 people who have been infected by the coronavirus in China's Hubei province had digestive symptoms such as diarrhoea.
Another common symptom of Covid-19, as well as cold, flu and many viruses in general, is feeling tired or fatigued.
Being told to rest is common when you’re ill, but feeling tired and not being able to sleep due to coughs and difficulty breathing, can make things all the more difficult.
Jaimuay Sae-ung, 73, was the first Thai national to contract coronavirus in December last year.
Despite having underlying health conditions, including a heart problem, Jaimuay survived the illness after doctors isolated her at a hospital in Thailand for treatment.
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"I only knew (I had coronavirus) after I came to the hospital," the mother of seven told Sky News.
"I felt a bit sad, a bit shocked, tired and fatigued and I couldn't eat."
It is important to note that you may have had one or several of these symptoms but have not had Covid-19.