People who have one specific type of cough are being urged to see their GP over fears they could be one of 600,000 'missing' cases of a serious illness.

In late autumn it's quite normal to have cough, sore throat or a combination of the two, as spending more time indoors means viruses spread more easily from person to person. In most cases the common cold is to blame, and symptoms should pass within a few days.

However, if you have a persistent chesty cough producing phlegm that does not go away, you could be showing signs of Chronic obstructive pulmonary disease (COPD). Left untreated, this condition can lead to serious health problems, such as pulmonary hypertension, pneumonia, and heart disease.

Currently, 1.7 million people are living with COPD in the UK, and around 600,000 are living undiagnosed, according to the charity Asthma + Lung UK. Most people with COPD do not have any noticeable symptoms until they reach their late 40s or 50s, though it can be diagnosed earlier - particularly in people who smoke, or have smoked in the past.

According to the NHS, the most common symptoms of COPD are:

Less common symptoms of COPD include weight loss, tiredness, swollen ankles from a build-up of fluid (oedema), chest pain, and coughing up blood.

Symptoms will often present infrequently at first, before gradually getting worse over time. More severe cases of COPD can affect your ability to breathe, and make day-to-day activities increasingly difficult.

If you have persistent symptoms of COPD, you should make an appointment with your GP.

A doctor will usually examine your chest and listen to your breathing using a stethoscope. They also may ask you to breathe into a spirometer, a device which measures the volume of air inhaled and exhaled to assess your lung function.

Though there is no cure, COPD can be treated with inhalers and tablets to help with breathing, along with pulmonary rehabilitation, a specialised programme of exercise and education which can improve your quality of life.

The main way of reducing your risk of developing COPD is by stopping smoking. Even people who are already diagnosed with COPD can see significant improvements in their health after quitting.

People with one type of cough urged to see GP 'as soon as possible' - The Mirror