LONDON — Go-Ahead Group Plc, the largest operator of buses in London, may double the size of its U.S. school bus venture following a positive start to the project last month, according to the company’s CFO Nick Swift.

The business, which is run in conjunction with U.S. partner Cook-Illinois Corp., operates about 120 yellow school buses in St. Louis, and the number is likely to rise to as many as 300 vehicles in 2011, Bloomberg reports.

“It’s the potential we’re encouraged by,” Swift told Bloomberg. “It’s a nice low-risk start up and a nice-sized contract, so if we could get to two or three hundred buses next year, terrific. We can gradually build it that way.”

Go-Ahead is diversifying its operations to reduce reliance on the U.K., where the company said it is cautious about the outlook because of economic uncertainties.