Congestion charging, which will be introduced to central London on February 17, will cost the John Lewis Partnership an estimated£200,000 in licence fees alone.
The impact on shoppers, however, is much harder to quantify. 'We simply don't know how price sensitive the car-borne shopper will be,' said a spokesman.
Less than 10 per cent of customers to JLP's Oxford Street store, where the main impact will be felt, come by car.
Also affected will be JLP's Waitrose supermarkets on Marylebone Road, Clipstone Street and in Victoria.
The total licence fees are calculated by estimating deliveries during the charging period, which runs from 7am to 6.30pm on weekdays. Not included are journeys made by company cars within the group and this may add up to another£80,000 a year.
The situation for other retailers appears to be similarly unclear. Regent Street Association director Annie Walker said the impact may prove positive.
'If it reduces traffic and makes Regent Street a more pleasant place to shop, then it could be beneficial,' she said.
Her organisation opposed the introduction of the charge, but she admitted it is unclear as to what will happen. 'The traffic experts I spoke to said they simply didn't know,' she added.
A negative impact could arise if shoppers are deterred or carriers increased prices for deliveries, she warned.