British Open leader Phil Mickelson dropped a shot for the first time in this year's Open championship during his second round on Friday morning when he bogeyed the 12th.

The American missed his par putt at the 430-yard par-four to drop back to two-under for the day and 10-under for the championship.

He had earlier enjoyed three birdies on the front nine, including one at the short eighth where he came within just a few feet of holding his tee shot.

The 2013 Open champion equalled the lowest score at a major with an eight-under 63 on Thursday, only being denied the first ever 62 when his birdie putt at 18 lipped out.

Mickelson's round began in drier and calmer conditions than had been forecast but the rain began to fall heavily by mid-morning.

In the worsening conditions Mickelson led by three from a group of four players including reigning Open champion Zach Johnson.

Johnson was three-under for his round at the turn and seven-under altogether, level with fellow American Keegan Bradley, Denmark's Soren Kjeldsen and Sweden's Henrik Stenson.

Germany's Martin Kaymer had also been at seven-under overall at the turn but a triple-bogey seven at the 10th was followed by a bogey five at 11 as he dropped back to three under par.

Source: AFP