ON a searing day in August 1970, three Scotsmen walked off an aircraft at Kai Tak airport - and changed the face of Hong Kong soccer. Twenty-three years later, two of the three of early adventurers are still in Hong Kong and doing nicely, thank you. Derek Currie, public relations chief for Carlsberg brewery, and Walter Gerrard, sales chief for the Hiram Walker drinks concern, can now comfortably look back on those early days when they made history. The third member of the band of the first overseas soccer professionals to play in Hong Kong was Jackie Trainer, who returned to England before drifting out of the game in the early 1980s. Surrounded now by medals, mementoes and scrapbooks which recount the heady days of early professional soccer in Hong Kong, Currie and Gerrard remain firm friends and recall some great moments. ''I suppose all old pros look back and say: 'It just isn't the same today'. But, in truth, it isn't. And how can it be?'' asked Currie. ''We were the first, and in those first three seasons Hong Kong had never seen anything like it.'' Gerrard said: ''Can you possibly imagine today a crowd of 27,000 people turning up to see a game involving the Army amateur team? Rangers tapped into a phenomenon and, in the end, we were the benefactors.'' The key words in that statement are ''in the end'' because neither Currie nor Gerrard were particularly well paid for their efforts. But they did lift Rangers to super-stardom, and then went on to play for Seiko where their rightful rewards followed. I can still recall the first game the three men played at the old Boundary Street ground. It was in early December and their opponents were Happy Valley, back into the First Division after quitting the league in the bitter days of communist violence in 1967. The previous season Rangers, despite their excellent young Chinese players, had languished. But they were revitalised by Currie, Gerrard and Trainer - and a sellout crowd of 10,000 turned up. It was the beginning of the glory days for Hong Kong soccer which lasted until the early 1980s and have not been seen since. ''It was a great time for us all. There were some great characters around, in and out of the game, and the public just loved their football,'' Currie said. Since then an innumerable flow of foreign players have followed the professional pioneers who put soccer on the map in the territory's sporting life.