His victory earned pounds 116,000 and lifted him to 13th in the Ryder Cup points table. He agreed it was the greatest moment of his career, but the 25- year-old from Madrid refused to speculate on whether he can follow his father Antonio into the European team.
"I played sensibly today because I knew I had a big lead and did not want to waste it," he said. "I was very solid. It was not easy because it was quite windy and the pressure is big at these moments, especially on the back nine.
"I just tried to keep making pars. I hesitated on a couple of shots and bogeyed both the seventh and ninth. But then I had pars all the way home until I got my only birdie at the final hole."
Claydon began the day 10 shots behind Garrido in joint 12th but scored a best-of-the-day 66. He had seven birdies, including four in five holes from the 12th. With two holes to play he had closed to within two shots of the lead but then he dropped a shot at the 205-yard 17th. Claydon said: "I hit a terrible shot there and with it being so wet you can't get out of bunkers too well.
"But I can't complain. The real damage to my chances came in the third round when I had an awful putting day and shot 72."
James, seven times a Ryder Cup player, had an up and down round with three bogeys and two birdies in his final 72 but the pounds 43,820 he won for third place has not done his Ryder Cup chances any harm.
Bernard Langer shot 69 for 277 to finish joint fourth while Ian Woosnam shot 72 for 280 to end joint 13th with Sweden's Robert Karlsson.
Results, Digest, page 23