JUDY MURRAY has called for the authorities to relax the rules on playing in extreme weather conditions after Wednesday witnessed the hottest day at Wimbledon since records began.

With temperatures on site officially recorded at 35.7 degrees Celsius and a ball-boy fainting out on Court No.17, Murray said that player safety should be paramount.

While women’s tour matches can implement a 10-minute break between sets two and three when temperatures exceed 30 degrees, there is no such uniform rule in men’s matches, which can stretch to four or five hours.

“You cannot mess with people’s health,” said Judy. “You need to take the advice of doctors and sports scientists as to what the rule changes should be.

"At what point do you stop a match and at what point do you stop a match from going on? And do you allow them to take breaks to rehydrate or recharge, or whatever it is?

“We Scots are not known for our ability to cope with severe heat or sunshine – we do not get much of it,” said Judy.

“But because Andy trains in Miami he trains in the heat and the humidity a lot. He is probably as equipped as anybody to be able to deal with it. It doesn’t make it any easier, but he is probably a little more used to it.

“Andy has been quite fortunate in Australia in that he has been put on the bigger courts that have the roofs, and the roofs can come across to provide some comfort from the sunshine.

"I watched Jamie play a doubles match in Australia and he had heatstroke after it. He was four hours in the locker room just shaking and that was really, really worrying because he was afraid.

"And I couldn’t go in the locker room so I had to phone Andy and say ‘come, Jamie is in trouble and you need to be with him’. So he rushed from his hotel and hung out with him and the doctor. But that is really scary because you don’t really know what is happening.”

The heat will be less extreme on Thursday and showers are also forecast, but the Scot’s match – first up on the roofless Court No.1 – should be finished.

Judy recalls the dramas her son has had against the Dutchman, at last year’s Australian Open he cramped up badly during the third set before winning in four, and hopes for a less eventful win this time around.

“Haase has nothing to lose,” said Judy. “He has a big forehand and likes to run round his backhand a lot and has quite a big first serve. But Andy knows his game well so if he plays his best, fingers crossed.”