As soaring temperatures prompted the Met Office to issue a heat health warning this week, the TUC has called on employers to keep indoor workplaces cool and relax dress codes so staff can work as comfortably as possible.

The union body says bosses can help their workers through simple measures. It says firms can move staff away from windows, install ventilation or air cooling, or open windows where safe and possible. Relaxing dress codes can also help workers cope. And flexible working could allow workers to dodge the hottest parts of the day or a sweltering commute. Frequent breaks and a ready supply of cold drinks will help staff stay comfortable too. The TUC warns that high temperatures can lead to sickness, a lot of concentration, and slippery, sweaty palms – all of which can increase risks at work. And overheating workers, faced with a choice between heat stress and other hazards, may feel they have to ditch uncomfortable safety gear.

TUC General Secretary Frances O’Grady said: “It’s no fun working in a baking office or factory and employers should do all they can to take the temperature down. The most simple way for staff to keep cool inside when it’s scorching outside is being able to work in more casual clothing. While shorts and vest tops may not be appropriate for all, nobody should be made to wilt in the heat for the sake of keeping up appearances.” The TUC leader added that “bosses who provide a cool and comfortable work environment are going to get more out of their staff. Workers who are unable to dress down in more appropriate summer clothing, or who work in offices without air-conditioning, fans or a plentiful supply of cool drinking water, are going to feel lethargic, and lack inspiration and creativity.”

The TUC has also warned that measures must be taken to protect outdoor workers, including scheduling work to avoid the hottest parts of the day, providing shelter and canopies to shade workers from the sun, providing sun screen and suitable clothing and hats to protect the skin, and providing breaks and a ready supply of cold drinks.

This week sweltering London Underground staff were given permission to wear shorts and promised better air conditioning in staff rooms, a move pressed for by Tube unions.