tick-tacker
 n.— «Perhaps the tick-tackers—sharp little blokes with white gloves who conveyed betting information with their hands from vantage points—and a few other key ingredients were missing, but the feel was similar.…Tick-tackers were tolerated on British tracks long after being barred in Australia because the racing over there needed the custom.» —“Just Like A Day At Manchester, And Look What Happened To It” by Max Presnell Sydney Morning Herald (Australia) June 23, 1995. (source: Double-Tongued Dictionary)