Saharan red dust from the continent could cause problems for those with breathing difficulties, as experts have warned of spikes in air pollution causing smog to build over Britain.

Asthma sufferers and older people are being advised to "reduce physical exertion" particularly while outdoors, as the air becomes more dense with pollutants.

Dr Sotiris Vardoulakis, head of the air pollution and climate change group at Public Health England's Centre for Radiation, Chemical and Environmental Hazards, said: "While most people will not be affected by short term peaks in air pollution, some individuals, particularly those with existing heart or lung conditions, may experience increased symptoms."

The Department for Environment, Food and Rural Affairs (Defra) has warned of spikes in air pollution across central, eastern and northern England.

Additionally, with summer seeming to come early for many this week, doctors have reported seeing hay-fever sufferers experiencing symptoms.

While the pollen levels are moderate for much of the south of England and low for the rest of the UK according to the Met Office, many people are already suffering from hay-fever symptoms.

Andrew Williams, nurse consultant at Homerton Hospital, east London, told the Daily Express: "People have already been coming in with symptoms triggered by the London plane trees.

"Now we are seeing high birch pollen levels, a lot of sufferers are presenting slightly earlier than usual as the problem gets worse."

The country could enjoy the hottest day of the year so far today as temperatures are expected to soar to 22C (71.6F), making parts of it warmer than Greece and Turkey.