The hottest city in the UK heatwave has been forecast by the Met Office - and it's not London.

The heatwave has officially begun today, and the weather is set to get even hotter in most of the country from today until Saturday, when temperatures are expected to peak, according to the latest Met Office predictions. While London is usually among the hottest cities in the country thanks to its giant urban sprawl and its southern location, it's not set to be the warmest city this Saturday, when temperatures will be at their hottest. According to the forecaster, London will be 31C on Friday, dropping to 30C on Saturday and staying level at 30C on Sunday.

While that's plenty hot enough, it's not the hottest city. Cardiff, the Welsh capital, will be even hotter - 31C on Friday, 31C on Saturday, and 29C on Sunday.

But Bristol, a stone's throw over the Severn from South Wales, will be slightly hotter again - 32C on Friday, a truly sweltering 33C on Saturday and 31C on Sunday, the hottest major city in the Met Office forecast.

In fact Bristol beats Truro in Cornwall (only 27C on Saturday), Exeter in Devon (28C) and south coast cities Brighton and Bournemouth, which can only manage 27C on Saturday.

Birmingham will be among the hottest cities, with 32C on Friday, 31C on Saturday and 29C on Sunday, while northern cities like Leeds, Sheffield and Manchester will all reach 30C conditions too.

The UKHSA has issued yellow heat health alerts for every region of the UK, which took effect at 11am today (Thursday, July 10) and will remain in place until 10am on Tuesday, July 15.

But the Met Office is predicting that the heat will fall away next week and the heatwave is likely to end early next week as a 'cold front' arrives from the Atlantic - though more hot weather is still possible.

The forecaster says in its long-range forecast for July 14 to 23: "The heatwave from the weekend will be gradually eroded from the west early next week as a cold front arrives from the Atlantic.

"This will bring the chance of some heavy rain or showers, perhaps thundery, especially in northern and western areas.

"Towards and beyond midweek, a rather changeable pattern is anticipated with some rain or showers possible at times, which could be heavy and thundery, and particularly focused in western and northwestern areas.

"Longer drier spells are most likely towards the south and east, although even here some showers may be possible at times. Temperatures are likely to remain above average, especially in the south and east where further spells of very warm or hot weather remain possible."