Jamie Murray has joined Heather Watson in questioning the direction in which British tennis is heading.
Watson's defeat by Fiona Ferro on Tuesday meant British hopes in the singles at the French Open were ended in the first round.
Former British No 1 Watson questioned where the next top-50 players are coming from and criticised the Lawn Tennis Association's strategy of investing heavily in a small number of players at both professional and junior levels.
National academies in Stirling and Loughborough will support up to 32 players - the initial intake was 16 - aged between 11 and 18. There is financial support for a much wider number of players but not at anything like the same level.
Murray, who is through to the second round of the doubles in Paris with partner Neal Skupski, said: "I think it's very difficult for you to tell me that this 13-year-old kid is going to be a great player and my 13-year-old kid is not going to be a player.
"With all the money that is at their disposal, I think the governing body needs to get the grass-roots programmes as best as they possibly can because that's what brings people into the game. The more people you have playing the game, the more chance of having a bigger pool to fish in, basically.
"They're obviously trying to improve on both things (grass-roots and professional) but it takes time. Even with the academies, you will only see in five, six, seven years down the line if these have been successful and whether it has been the right play.
"It is impossible to say now if it is the right or wrong decision to go with that. They obviously are so let's get behind it and hopefully they have got the right people running these academies to get the best out of these kids that have been selected to go there.
"For me, right now, that is probably the most important thing. Because, if not, it is a massive waste of money.
"I want to see more players playing at the top of the game. We are getting excited that Liam Broady qualifies and we have six players in the main draw. But really? Come on.
"We are a Grand Slam nation, we should have at least double that, in my opinion, with the resources we have available. I don't see how anyone can disagree with that."
The academy system was the brainchild of former performance director Simon Timson, who put in place a 10-year plan in 2018 but left this summer to join Manchester City.
Timson will shortly be succeeded by Michael Bourne, who, like his predecessor, comes from UK Sport instead of a tennis background.
Murray said: "Personally I'd prefer to see someone from tennis there who is really invested in British tennis and wants to see it succeed and is willing to be there for five, six, seven, eight years if that is what it takes to put the right structure in place and see it through."
The 34-year-old did, though, offer words of support for chief executive Scott Lloyd, who has been in the role since the beginning of 2018 and inherited a high-performance system that was virtually non-existent.
Murray said of Lloyd: "I really hope he is doing a good job. I like talking to him about British tennis and what is going on. He really cares, which is a huge thing I think. Hopefully we will start to see the fruits of his labour and what he is putting in place."
Lloyd quickly made it known that he was unimpressed by Watson's comments, particularly her assertion that she would not want to take up a role with the LTA because of politics.
"I don't recognise much of Heather's interview," Lloyd said. "In particular, I think that the politics she talks about is not something I see at the LTA. I prefer to try to get things done.
"We have confidence in the new group of female players coming through on our pathway. After Jo (Konta) and Heather, 10 of the next best 12 players are all aged 25 or younger.
"I have absolute belief in the performance strategy, the approach we launched two years ago, as a long-term plan focused on what it takes to win at the elite level."
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