Andy Murray is preparing to serve to a seven-year-old boy – but his opponent need not fear.

The world No4 tennis ace has a ping-pong ball in one hand and a biscuit tin lid in the other.

It’s safe to say this won’t be one of his ferocious 145mph thunderbolts.

Instead, the ball clangs off the lid at more like 1.45mph and bounces on a trestle table before sailing over a “net” made up of baked bean cans.

With just a few days to Wimbledon, Andy’s squeezing in some highly unorthodox practice – and loving every minute of it.

The 24-year-old, who has dropped in on a school sports day in south London, laughs: “I love doing stuff like this. As soon as I walked in here and I saw the kids it made me smile. I LOVED sports day.”

Andy has fond memories of playing all-sorts of sports with older brother Jamie, a former Wimbledon mixed doubles champion, and their tennis coach mum Judy, 50.

And now Judy has set up a series of games – including the biscuit tin ping-pong exercise – to encourage parents to play games with their kids.

It’s a bold initiative from a woman once described as “the pushiest parent in the Western world”.

Andy says: “I think a parent’s job is to support their kids whether they are winning or losing.

“But when you start to play sports seriously you have to learn to be very competitive. You need the right mix. We were never, ever pushed into playing sport.”

Judy, who split from husband Willie when Andy was nine, was a talented tennis player herself and coached both her sons very early on. But, as Andy rose to fame, her presence in the front row at his games, cheering and punching the air, seemed to irritate fans and commentators.

In March, ex-Wimbledon champ Boris Becker accused Andy of being a mummy’s boy and claimed it was time for him to cut the apron strings.

So, did he want to thump Boris?

Andy frowns and says quietly: “Well, he has made many mistakes in his career too. There are a lot of things he has done in his life that I would never consider doing.

“I don’t know why mum’s support gets taken out of context. Rafa Nadal is coached by his uncle and his parents are at all his big matches and Roger Federer’s parents are there all the time but people don’t talk about it. But just because my mum is a tennis coach they say she is coaching me and getting really involved in my tennis and that isn’t the case at all. She isn’t my coach. She’s there to support me because that’s what mums do.”

As for Judy, she shrugs off any criticism.

She says: “There’s this real misconception that I am constantly around Andy, telling him what to do, but I only go to about six tournaments a year. When I do go, yes, I sit in the box and support him the same way I always have done. Andy jokes about the slow-motion replays of me screaming and punching the air.

“But I’m not there trying to influence his game.”

Andy’s game is in fine nick and the nation hopes he can at last become the first male Brit to win the Wimbledon single’s title for 75 years – when Fred Perry lifted the trophy in 1936.

Expectations were raised yet another notch when he lifted the AEGON Championships at Queens on Monday.

“The build-up to Wimbledon is difficult,” he admits. “But once the tournament starts it’s fine because you are concentrating on the tennis, on your game.

“This week I’ll be doing a lot of training but I also have a lot of downtime, too.

“I just do normal things – I take the dogs out for walks, go out for dinner, play on the Xbox.

“I grew up watching Tim Henman and all the attention he got at Wimbledon and in the run-up and while I never thought that was going to be me it wasn’t a shock. I do my best and it’s fantastic to have so much support.

“But I really don’t feel pressured by people’s expectations of me because no one’s expectations can be higher than mine. I’m going into Wimbledon believing and hoping I can win it.”

Andy, who lives with 23-year-old English graduate Kim Sears, certainly seems remarkably relaxed as he helps launch his mum’s Set4Sport initiative.

A couple of dozen children and their parents pelt him with balls of all shapes and sizes – and he barely bats an eyelid when I accidentally whack him in the face with a ping-pong ball during a quick photo shoot. Andy says: “This is great. The games mum has devised come from the games Jamie and I used to play at home as kids with mum and dad. We started off playing swing ball in the garden but we loved all kinds of sports, football, squash, gymnastics, or just hitting stuff around.

“We’d play tennis in the front room with a soft ball and toys lined up to make a net or get a balloon filled with water and try to smack it through two arches in the hall we used as goals.

“It could get a bit rough – we broke a few windows!”

At Wimbledon, Andy will hope he can break a 75-year duck instead.

3 Set4Sport is a new programme from Judy Murray in association with RBS, showcasing easy ways for parents to play with their children. For more information visit www.Set4Sport.com