Holidaymakers heading to Spain and Portugal have been warned of an extreme heatwave which could see the hottest-ever temperatures recorded in continental Europe.

It comes as the heatwave which has hit Ireland and across Europe is expected to continue following more comfortable temperatures this week, with high temperatures expected across the continent and in parts of the UK.

A British Met Office meteorologist said the current record of 48C in Athens, Greece, in 1977 could be broken as a wave of blisteringly hot air sweeps in from Africa.

Temperatures crept into the low 40s yesterday and are expected to rise and peak at the weekend, with the highs expected inland rather than in coastal areas.

He added that these sorts of temperatures are not only exceptional for the locals but tourists will never really have experienced them.

In pictures: Soaring temperatures across Europe

"Combined with high pressure in charge, blue skies every day, and the ground already warmed up, that leads to a day-on-day build, combining to give us these intense temperatures," the official said.

Temperatures in southwest France could also rise to the high 30s.

Portugal is on high alert due to the expected temperatures, with the government warning of a high risk of forest fires.

The highest temperature on record in Portugal was 47.3C in 2003, in the southern Alentejo region.

Several places in the Alentejo are forecast to reach 47C this Saturday, while Lisbon could reach 43C, which is highly unusual for Portugal's capital by the sea.

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Portugal's government issued a "situation of alert", raising the readiness levels of firefighters, police and emergency medical services until 6 August.

There is a ban on lighting fires and access to forests will be limited.

Scorching temperatures have also devastated crops across northern Europe, with parts of France and northern Germany showing serious damage to wheat yields.

Sweltering heat has also hit parts of Russia and Romania, as well as Scandinavia and Baltic states.

Britiain's Met Office said mercury could climb back up to 31C in London this weekend - with sunshine returning to most of the country.

Meanwhile, the weather is set to improve in Ireland after a week of heavy showers.

The best of the sunny spells will be in the east and south of the country but temperatures are set to reach 23C on Sunday. 

Northern Ireland will enjoy temperatures in the mid-20s, with scattered outbreaks of rain.