A BOY diving for golf balls in a park lake drowned despite desperate efforts to rescue him by two young friends and two golfers who plunged into the 15-foot deep water.Craig Summerfield, who was due to celebrate his 12th birthday on Sunday, is believed to have suffered cramp in the cold water. He plunged to the bottom of the lake at Heaton Park golf course, near Middleton, in less than a minute.Today his tearful parents Colin, 41, and Patricia, 37, of Harry Thorneycroft Walk, Beswick, spoke of their anguish and called for the lake to be fenced off.''We are just completely devastated,'' said Mr Summerfield, a bus driver. ''He was such a good kid, with lots of friends; everybody liked him.'' He added: ''I can't understand how a pond like that could be so easily accessed by youngsters.''Craig had gone out to play with his two friends who live near Heaton Park yesterday afternoon. The three stripped to the waist and started diving into the water to collect the golf balls on the bottom. It is thought the boys could have been competing with each other to see who could retrieve the most balls. When Craig started struggling in the water his two friends tried to help then raised the alarm. Two golfers jumped into the water but their efforts to save him were in vain.Firefighters were called to drag the lake and a police underwater search team found Craig's body several hours later. His two pals, upset and suffering from shock, were taken for a check-up at North Manchester General Hospital.Station officer Gordon Laverick said: ''The water on the surface was warm because it was a warm day, but underneath the water could have been very cold and people need to be aware of this.''If these three youngsters were playing, others must be playing, too, but this terrible tragedy shows the dangers. It may have seemed like a harmless game but it has taken the life of a young boy.''Golfers who regularly use the municipal course say youngsters frequently play around the lake and many risk danger by attempting to retrieve lost golf balls from the water, selling them back to players.The lakeside can be easily reached from footpaths linking the golf course with the main park area. Craig, who was taken to Booth Hall Children's Hospital, had one brother Colvin, 19, and two sisters Cheryl, 17, and Carina, 15.His father said Craig had just finished his first year at Wright Robinson Sports College. ''He was just a normal lad, he loved football, and he loved playing on his Playstation. It's such a waste.''A post mortem was being carried out today.