By Jeremy Lovell

LONDON, April 27 (Reuters) - This month is set to be the warmest April in Britain since records began nearly 350 years ago and all over Europe tourists are slapping on the sun cream several weeks ahead of schedule.

Britain's Met Office said the average temperature in central England from April 1-25 was 11.1 degrees Celsius, 3.4 degrees above the norm and the highest since records began in 1659.

Temperatures from Belgium to Italy are averaging more than three degrees above the 30-year norm.

The office added there was a big chance of a repeat of the European heatwave of 2003 which killed some 35,000 people and which scientists attributed to global warming.

As the spring rain stayed away, sidewalk cafes and outdoor leisure parks across Europe reported booming business but grain crops are showing signs of drought stress.

In the Netherlands, the KNMI weather institute said this month had already broken records as the warmest, driest and sunniest April and noted global warming was one of the reasons.

The Netherlands has not had rain since March 22 and April is set to be the driest in at least 100 years. Farmers have started pumping water from canals and rivers to irrigate their crops.

Germany has also recorded the highest April average temperature at 12 degrees, and the most hours of sunshine at more than 276, since records began in 1901, according to preliminary estimates by the German Weather Service (DWD).

The lack of rainfall prompted several German states to issue warnings about the risk of forest fires which have hit neighbours Switzerland and Austria.

Drought has hit Hungary's key grain regions and may severely reduce grain and oilseed crops, leading trading firm Agrograin said. "In mid-April the average temperature was 5-6 degrees Celsius higher than usual," said meteorologist Gyorgy Gyuro.

Italy's river Po, which waters the region accounting for one-third of the country's agricultural production, fell on Sunday to 6.53 metres (21 ft 5 in) below its normal level at one control point, having fallen 80 centimetres in a week.

Britain's Met Office said there was a one in eight chance of temperatures in the three summer months -- July, August and September -- repeating the 2003 and 2006 heatwaves.

"In meteorological terms that is really quite a high probability," a spokesman said.

On Friday, Britain's Department of the Environment warned of summer smog at the weekend with high ozone levels endangering the ill and elderly. But in contrast to 2006, Britain was at least not facing a drought after a mild and very wet winter.

In Germany, one newspaper said soaring temperatures could inflame libidos.

"Skirts are getting shorter and there is more bare flesh flashing," Germany's biggest selling newspaper, Bild, wrote, warning Germans to keep a close eye on their partners.

"The heat excites the sex hormones much more strongly, disturbs the sleep and stimulates lust." (Additional reporting by Reuters' European buros)

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