Andy Murray has blamed the Lawn Tennis Association for hampering older brother Jamie's tennis career.
Murray, 18, teamed up with his brother for a doubles win on Sunday as Scotland beat England in the Aberdeen Cup.
"He was number two in the world when he was around the age of 13," the world number 65 said of his brother.
"Then he went down to an LTA school in Cambridge and they ruined him for a few years. It was their fault. But I really want him to come back and do well."
The LTA has reacted to Murray's criticism, with performance director David Felgate stressing that there was no uniform way of bringing on players.
Felgate, Tim Henman's former coach, said the LTA had backed Andy Murray's move to Spain to develop his game.
"The LTA recognises that different players react to different approaches which is why we have introduced choice and flexibility into our performance system and continue to support our best players wherever they want to train," said Felgate.
Jamie is 15 months older than Andy and, despite reaching the doubles semi-finals of the junior US Open with his brother in 2004, is currently at a career-high of 896th in the world.
"My brother is very talented," added Andy Murray.
"He is a good guy and he works very hard. He wants to be a tennis player and I think he has shown he has the talent."
None of the current top three British players - Tim Henman, Rusedski and Murray - came through the recognised LTA coaching ranks as youngsters.
Rusedski grew up in Canada and moved to Britain as a ready-made top-50 professional, while Henman also developed largely outside typical LTA coaching structures.
The younger Murray spent the formative stages of his career learning the ropes in Spain, albeit with the aid of LTA financial support.
Rusedski was more diplomatic about the standard of the UK's coaching infrastructure, but also recognises the problems.
"Things are getting better but there is still a lot of room for improvement, that's for sure," said Rusedski.
But it is also about finding those kids who have something different and finding parents who are really involved with the kids.
"Judy (Murray) is very involved with Andy's tennis and he is quite a fighter and a character. He is not your average young person.
"It is about finding the kids that are like that from a young age and whether they are in or out of the system, trying to find a way to develop them. There has to be a way to work it."
The England v Scotland team competition finished 4½-2½ at the weekend as the young Scot beat Greg Rusedski in the final singles match to seal victory for his side.
Earlier, the Murray brothers had beaten Rusedski and David Sherwood 6-3 2-6 10-5, the third set on a first-to-10 points system, in the doubles.