The Edgware Road dealership in London said the previous result of 345 units in one month (set four years ago) was beaten due to its Prius sales.
"London’s Mayor Ken Livingstone and his partner recently have bought a Prius from the capital’s Jemca Toyota – but it was the concerns of fellow-customers about the Mayor’s congestion-charging policy that helped boost the centre’s September sales to the highest ever recorded in any one month by a Toyota dealership.
"We sold 111 Prius cars in September, and the majority were top-of-the-range T-Spirits," said Jemca sales executive Roger Hart.
"There’s no doubt that much of this was driven by concerns over the extension of congestion-charging west into Kensington and Chelsea next February," he added.
Drivers of the Prius are exempt from the £8 daily congestion charge.
Also selling particularly well for Jemca in September, reflecting a general pattern for Toyota in retail sales, were its smaller low-emission, fuel-saving cars, including the Yaris supermini (77 units), Corolla (37) and Aygo (25), while 33 4x4 enthusiasts became RAV4 owners.