Overnight leader Graeme Storm retained top spot after the second day of the KLM Open.

Storm began the day with a two-shot advantage over Martin Kaymer, Fabrizio Zanotti and Raphael Jacquelin.

He returned a score of 66, his second bogey-free round to the tournament, to extend his lead to three over Gonzalo Fernandez-Castano, Scotland's Scott Jamieson and Sweden's Peter Hanson.

Ireland's Simon Thornton jointly hit the best round of the day to finish on five under, with Damien McGrane two shots further back.

After his round, Storm said: "It makes a change to have all red on my card.

"Hopefully I used all the bogeys up last week in Crans and long may it continue.

"I wasn't expecting to shoot four-under. I just managed to go round and keep the bogeys off the card as I did yesterday and made a few birdies."

Fernandez-Castano, the 2005 winner on this course, is looking to put the disappointment of failing to make the Ryder Cup team behind him.

"My year has been disappointing to say the least. I didn't play well over the summer," the Spaniard, who shot a 65, told europeantour.com

"Hopefully I can improve this second half, hopefully with a win, and maybe here as it is a course I like very much."

Scott Jamieson raced into contention with a 64, the joint-best round of the day, after picking up seven shots in his first 10 holes having started at the ninth but a bogey at the sixth pegged him back slightly.

"Being four under after four holes was a very hot start and a couple more of them would be great," he said.

"Six under par on any day is great but especially on a course like this where it is tight off the tee."