Asthma attacks are three times as common as previously thought, according to new figures which have sparked warnings about the impact of air pollution.
Data from the charity Asthma UK suggests that every three seconds somebody in the UK has an attack.
Its figures suggest 10 million such episodes annually, when previous figures suggest around three million attacks annually.
The charity surveyed more than 10,000 people with asthma, who reported having an attack on average twice a year.
Its experts said some of the rise could be attributed to the fact that previous attempts to estimate the total number of attacks only measured the amount of medication used, missing cases where patients struggled without an inhaler.
But they also raised concerns that growing numbers of children and adults were suffering from breathing results as a result of air pollution, and of poor NHS management of their condition.
Asthma attacks can be life-threatening, with three people on average dying every day from an attack.
The condition affects the airways, narrowing them and making it harder to breathe.
Triggers can include cold air, coughs and colds, and grass pollen.
Dr Andy Whittamore, clinical lead at Asthma UK, said: “It is shocking to think that every three seconds in the UK someone could be having an asthma attack, a terrifying experience than can cause distress and in some cases prove fatal.
“Asthma attacks do not come out of the blue and if people recognise the tell-tale signs that an attack is about to strike, they can get the help that could save their life.”
The charity warns that if people need to use their reliever inhaler (usually a blue colour) three or more times a week, or are are waking up at night because of their asthma, they should contact their GP.
They should also seek help if their symptoms, such as wheezing or a cough, are getting worse or are interfering with their usual activities.
Those with a preventer inhaler (usually coloured brown) should take it daily to help build up protection against asthma attacks.
NHS data shows there were more than 77,000 hospital admissions for the condition last year.
Dr Samantha Walker, Director of Research and Policy at the charity said: “This can be about lack of basic care – two thirds of asthma cases can be prevented with the right care – and also about being exposed to pollutants, whether that is pollen in the summer or exposure to industrial pollutants.”
“We see this anecdotally when people with asthma come into London from the countryside feeling perfectly fine – and six hours later they are in hospital.”
She said the condition needed to be taken more seriously, with patients given an annual review, and quicker intervention when they suffered an attack.
“Also we are concerned that people don’t intervene quickly enough in the event of an asthma attack, there is a complacency about it.”
Previous research has found Britain’s asthma death rate is among the worst in Europe, with a 20 per cent rise in deaths in five years.
Air pollution has been linked to an estimated 40,000 premature deaths in the UK.
An investigation by the Telegraph recently revealed that four in ten children in primary schools are breathing toxic air that breaches guidelines form the World Health Organisation.
The data found 3.7 million pupils are being exposed to high levels of pollution on a daily basis – with some of the worst findings among the youngest pupils.