The NFU has urged workers to cut the risks of exposure to the sun as the Met Office issued its first ever extreme heat warning.

Forecasts suggested temperatures could hit 33C in large areas of Wales, south-west England and parts of southern and central England.

The warning, suggesting there was a risk to health, was expected to remain in place for at least 48 hours.

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Heat

The NFU said that working in extreme temperatures presented risks of exhaustion and heat stroke. It suggested workers and employers could take a raft of precautions to reduce the effect of the heat.

• Stay hydrated – ensure there is always a supply of water to hand
• Wear lightweight, light-coloured and loose-fitting clothing
• Slow down and work at an even pace
• If possible, avoid working at the hottest time of day or work in the shade
• Schedule frequent rest and water breaks out of the heat
• Use a damp rag around the neck to keep cool
• Eat cold foods, with high water content like fruit and salad

Be alert to signs of heat-related illness, including:

• Headaches
• Dizzy spells
• Loss of appetite and nausea
• Excessive sweating
• Cramps in the arms, legs and stomach
• Fast breathing and pulse, a temperature above 38C
• Intense thirst

Sun

In addition to the effects of the heat, the NFU warned workers of the dangers of long hours of sun exposure.

One of the most serious risks is skin cancer. Occupational UV exposure is an underlying factor in one death and five new cases of skin cancer a week in Britain, the NFU pointed out.

Under Health and Safety Executive guidelines, employers of outdoor workers have a legal duty to safeguard employees from the effects of UV radiation, it added.

Yet, surveys have shown only one in four outdoor workers wear suncream at work.