The organisers of the Great Scottish Run half-marathon have been out measuring the distance of the course.
There was controversy at last year’s event, when some competitors said they thought the course was shorter than the stipulated 13.1 miles.
Four cyclists set off from the city’s George Square at 04:30, and finished in two stages at Glasgow Green at about 07:00.
They were accompanied by a police escort whose job was to stop traffic.
The riders’ bikes were equipped with specialist measuring equipment.
New course record
The course should be 13.1 miles, but after last year’s event, some runners said they thought it was up to 200 metres shorter.
That difference could be crucial for professional runners – including last year’s winner Callum Hawkins, who also set a new course record.
If the course is found to be a different length, it mean’s the winner’s record, and that of all the other runners, could be in doubt.
The riders cycled the full half-marathon course, including going through a darkened Pollock Country Park.
The time and date were kept secret in advance, chosen in order to allow the officials an unimpeded ride.
The results of the measuring exercise will be announced on Monday by the run organisers, The Great Run Company.