It <i>will</i> be a glorious twelfth

All you sunworshippers out there, mark August 12 in big red pen in your diaries - for that's when a heatwave could hit.

Temperatures could exceed Britain's hottest day on record, with the mercury rising to a sweltering 39.6°C (103.4°F).

At least, that's what spread-betting company Sporting Index predicts, after looking at previous summers and forecasts by the BBC and Met Office.

The high temperatures are likely to hit from August 4 to August 12, it says.

'We cannot say where this is likely to be recorded, but it was more than likely to be in the South,' a spokesman added.

But, be warned - August 12 is a Friday. So either book the day off work now, or be ready to fight fellow workers for a coveted spot of grass in the park. There are no festivals on that date, but you could join the masses at Old Trafford Cricket Ground for the start of the Ashes Test between England and Australia.

Or head to Edinburgh for the Fringe or Military Tattoo.

The Met Office agreed the dates sounded about right and that the South is the probable location. But chances of such a scorcher were 'very remote'.

'Although global warming suggests these temperatures will one day be common place, that's not going to happen for at least 50 years,' a spokesman said.

Britain's highest temperature was

38.5°C (101°F), recorded at Brogdale, Kent, on August 10, 2003.