IT is the prerogative of every mother to worry about her sons.

The Scottish curse is to be a naturally fair-skinned race and the most concerned Judy Murray ever was about the on-court conditions her children had to contend with was in Melbourne last year.

The main object of her anxiety was her oldest son Jamie, who had collapsed with heat stroke at the conclusion of his doubles match with partner John Peers against Australian duo Matt Reid and Luke Saville. Playing tennis in 44-degree temperatures on one of the unforgiving, outside courts at Melbourne Park, it seems, wasn't the brightest idea.

While Jamie wasn't allowed to leave the locker room for four hours, his mother wasn't allowed in. Everything ended happily enough, but it is the kind of incident which leaves the Great Britain Fed Cup captain in no doubt that the sport's rules must be changed swiftly before someone somewhere doesn't make a full recovery. The heat at Wimbledon tends to be gentle by comparison but her number-two son still had to endure heatwave conditions on Centre Court on Tuesday.

"Andy has been quite fortunate in Australia in that he has been put on the bigger courts, and the roofs can come across to provide some comfort from the sunshine," said Judy, speaking at an event to promote Lavazza coffee in the Wimbledon queue. "But 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. Your body loses its ability to cool down."

The image of one of her sons cramping up is eerily similar to one witnessed the last time her other child took on Robin Haase, who Andy meets in the Wimbledon second round on Thursday. Last September in the US Open first round, the World No.3's body was briefly in spasms, particularly his quads and forearms, as he lost a third set 6-1 before making it through in four.

The other theme of the week, introduced by some rather injudicious comments by Boris Becker, has been players being given signals from the coaching box. "There is absolutely no chance of me sitting dead straight, as you well know," said Judy. While she feels some more coach interaction may help at junior level, she is unconvinced about it in the professional ranks. "You hear people shouting from the boxes all the time and if you are from an English-speaking nation it is very easy to pick up what you are saying. If you come from somewhere more obscure you could be shouting all sorts of things and no-one would have a clue what you are saying.

"In golf you have caddies giving advice and in team sports the manager or coach is always there to instruct during the course of the game," she added. "In tennis it does not really happen like that - it does on the WTA tour where the coach is allowed to come on once a set but in men's tennis it is one of the few sports where you are out there on your own. But I don't know if I would like it to change. It is one of the things I like most about the game, the fact it is so cerebral."