Mediaboss Marketing

London was the hottest part of the country, with temperatures reaching a maximum of 20.4C (68.7F) at St James's Park at 1pm, according to the Met Office.

This made the capital hotter than Madrid (17C/62.5F), the Balearic Islands (18C/64.5F) and the French Riviera (16C-17C/61F-62.5F), weather forecaster MeteoGroup said.

However the Met Office said there was a pollution warning level ten, the highest on their scale.

A level this high means adults and children with lung problems, adults with heart problems, and older people, should avoid strenuous physical activity, according to the Met Office.

People with asthma may find they need to use their reliever inhaler more often, according to their advice.

People are advised to reduce physical exertion, particularly outdoors, especially if you experience symptoms such as cough or sore throat.

Other parts of the south east of England will see the best of the conditions today, reaching between 17C (62.5F) and 19C (66.2F), meaning plenty of time in the sun for some on the first day of British Summer Time (BST).

The balmy weather will remain for much of the week ahead, according to Met Office meteorologist Eleanor Crompton.

"It will be warm but temperatures may be a down a couple of degrees. We'll see more cloud and hazy sunshine around with temperatures in the late teens from Monday to Wednesday."

Ms Crompton added: "There is a chance of some thundery showers coming up in western and central areas tonight, spreading to the north. It's the usual case of warm weather followed by the increased risk of showers."

More:
London is the hottest place in UK... but Met Office issues level ten alert for high pollution