France's Thomas Levet, who captured last year's title at Woburn Golf & Country Club's Marquess Course after surviving a four-man playoff, began the defense of his title with a bogey-free 68. He finished the first 18 holes tied for third with Ryder Cupper Phillip Price of Wales, Soren Hansen of Denmark, Scotland's Raymond Russell and Englishman Ian Poulter.
Scottish Amateur champion Barry Hume climbed to 5-under before closing with two bogeys over his last three holes. His 69 left him part of a 14-man logjam at 3-under-par.
Derksen, the winner of four straight Dutch Amateur Championships from 1993-96, and Luna, who won the European Tour's Madeira Island Open in 1995, each turned in cards with five birdies, two bogeys and an eagle at the par-5 seventh.
Luna, whose collection of clubs includes about 30 putters, chose a long putter before his round and was pleased with the results.
'I am glad I took the long one because I putted wonderfully,' said Luna, who also gained fame for beating Tiger Woods in the semifinals of the Alfred Dunhill Cup at St. Andrews in 1998. 'When I am not putting well the first thing I do is change the putter.'
Colin Montgomerie, the British Masters champion in 1998, has battled through a bad back to finish in the top-three in his last three starts on the European Tour. He shot 70 Thursday and was tied with Thomas Bjorn, Paul Lawrie, Justin Rose and 15 others at minus 2.
Full-field scores from the British Masters