The Great British Bake Off! Hottest June day for 40 years as heatwave continues

The temperature has reached 34.5C at Heathrow, west London, making it the hottest June day since 1976.

As well as marking five consecutive days that the mercury has soared past 30C, Britain's scorching heat has also topped temperatures in holiday destinations such as Lisbon, Marseille, Barcelona and Athens.

It is the hottest prolonged spell in June since the drought summer of 1976 and also the warmest summer solstice on record.

Britain's hot spell has seen the Met Office issue a level three amber heatwave warning, one step down from a national emergency, until Thursday.

Police in Cambridgeshire alerted motorists to melting roads, which forced the deployment of gritters in the area to shore up tarmac.

In the capital, London mayor Sadiq Khan has triggered an emergency air quality alert due to fears of toxic pollution.

Thousands gathered at Stonehenge on Tuesday night to welcome the sunrise at the ancient site on the longest day of the year.

Pagans, druids and other members of the public were watched over by armed police following the UK's recent series of terror attacks.

The highest ever temperature on a June day was recorded in Southampton on 28 June 1976, when Britons baked under 35.6C heat.

Social media users have been making light of the humid conditions, with Steven Lockett tweeting: "If you don't say 'it's too hot' to every person you see, are you even British?"

And an account named 'British Problems' noted: "It's so hot my marmalade liquefied."

On Facebook, a tongue-in-cheek trend saw users ask red-haired friends to mark themselves as "safe" in the heatwave.

The heatwave has seen Royal Ascot organisers abandon the event's dress code for the first time in history, with men allowed to remove their jackets on Tuesday.

Across the Wiltshire border from Stonehenge, thousands will travel to Glastonbury Festival in Somerset as the iconic music venue throws open its gates on Wednesday.

But the traditional Glastonbury mud could yet make an appearance, with thundery showers forecast on Wednesday night.

The heavy rain could drench parts of Wales, the Midlands, southern Scotland, northern and eastern England.

Flood alerts have even been issued for the North East.