The UK Health Security Agency has extended an Amber heat health alert, which was set to expire at 10am earlier today, to Wednesday.

Temperatures across Britain are forecast to reach highs of 34C today.

The alert is focused on five major regions in Britain: Yorkshire and the Humber, East Midlands, West Midlands, East of England, London, South East, South West.

A yellow heat health alert has also been issued for the North West.

The UK Health Security Agency has issued a second Amber heat health alert in just two weeks, with temperatures forecast to reach highs of 34C today

UK temperatures could be hotter than those in Mexico, Barbados, and Jamaica.

Britons should expect impacts on health and social care services due to the high temperatures, the agency warned.

Significant impacts include a rise in deaths, particularly among those aged 65 and over or with health conditions, and disruption to travel.

If the mercury tops 35.6C today, it will be the hottest June day on record.

The high heat will result in Britain being on drought alert with a "Mediterranean summer" threatening weeks of rainless skies.

Jim Dale, meteorologist for British Weather Services, said: “The southeast is looking like the Mediterranean, it is similar to what you would expect in Spain, and with more hot weather on the way, it is going to be unusually dry.

“This is where we start to worry about drought, because after the very dry spring, there is no sign of any significant rain on the way. We have had next to zero rainfall since winter, and there is nothing in the forecast, so although we are going to probably be talking again about heatwaves, the greatest risk is from drought and everything that comes with that.”

Today could also be the hottest start to Wimbledon ever, with the previous opening day record standing at 29.3C.

The Met Office’s three-month summer outlook predicts a 45 per cent chance of a hotter-than-average summer.

It warns further heatwaves are possible before autumn, with climatic factors to blame including a "global warming trend".

A spokesman said: “There is an increase in the likelihood of hot conditions which is consistent with our warming climate.

“This doesn’t necessarily mean the UK will see heatwaves and heat-related impacts but the risk of these is higher than normal during this period. There is a very slight preference for high pressure close to and across the UK, but this signal is rather weak.”