A dog walker was stopped on the course, while five men were spotted playing the 18-hole course without being members or paying “a suitable green fee”.
A spokesperson for the golf club said: “A very successful evening protecting the course and members of Haddington Golf Club.
“Sadly, five males were prevented from playing the course without being a member or paying a suitable green fee.
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“One dog walker was also reminded to follow the Scottish Countryside Code by keeping her dog on a short lead whilst walking on the course.
“Please also be aware that exercising your dog on the course is very dangerous and is not encouraged in any way.
“We will continue activities to check who is using the course over the summer time.
“Anyone who in interested in playing golf at Haddington should contact the pro shop in the first instance.”