Broadhurst, the defending champion, is through two rounds at 11-under-par 133 and leads by two shots over France's Christian Cevaer, who also shot a 69 Friday to reach 9 under.
Christian Nilsson shot a 1-under 71 and dropped from second place overnight into third place at minus-8. Fellow Swede Mattias Eliasson shares fourth place, one stroke further back, after firing a 5-under 67.
Eliasson was joined at 7-under by Jarmo Sandelin, who shot a 70.
Broadhurst, who equaled a course record with his 8-under 64 on Thursday, had an up-and-down round Friday.
On the front nine, the 40 year old collected three birdies -- including one on a putt of 60-plus feet at the second -- but dropped two shots with bogeys at the par-5 fifth and the par-3 eighth. That put him at 9 under around the turn.
Broadhurst moved into double-digit red numbers with a birdie at the 10th, but gave that shot back with a bogey at the par-4 fifth. He then picked up birdies at the par-4 14th and the par-5 18th to maintain his lead.
Afterwards, Broadhurst was less than happy about the way things went.
'I wouldn't say that it was one of the all-time great 69s,' he lamented. 'It felt difficult. It felt like a visit to the dentist at times.'
If Broadhurst can hang on to win, he would become just the second player after former Ryder Cup captain Sam Torrance to defend his title at this event.
'This is a tough track,' said Broadhurst, a six-time winner on the European Tour. 'I have just got to hang in there and hope that the bad shots are not too costly.
'If it was any other tournament and I hadn't shot 64 in the first round, I might not be quite so determined. [But] I don't want to give the trophy away too easily.'
While Broadhurst will be seeking win No. 7 -- and just his second in more than 10 years -- Cevaer is looking for his second victory on the European Tour. He mixed in six birdies with three bogeys in his second round.
Five players share sixth place at 6 under. Among them is Paul Lawrie, the 1999 British Open champion, who shot a 70. Lawrie is joined by Warren Abery (66), Gary Clark (67), Steven O'Hara (67) and Anthony Wall (67).
The cut line fell at even-par, with 76 players moving on to the weekend.
Meanwhile, The Golf Channel's 'Big Break IV' winner Paul Holtby missed the cut in his European Tour debut, shooting 76-69 to finish one back of the cut line.