They were shipped on a journey of nearly three hours by hybrid vehicle – but motoring experts said these could only manage a maximum of 40 miles by zero-emission electric power and the rest of the trips would have to have been using diesel or petrol.
The news comes days after The Scotsman revealed carbon emissions at the two-week event were likely to be more than double those of the previous UN Conference of the Parties (COP) conference in Madrid in 2019.
The sandwiches, included fresh batches delivered for the summit’s extra day on Saturday, were labelled as coming from Sandwich Larder in Aberdeen.
Catering firm Levy UK & I, which runs SEC Food, sold the sandwiches at a series of temporary cafes at the conference but said any carbon emissions would be offset.
Its spokesperson said: “We looked at a number of Scottish sandwich suppliers who could supply the high volume that was required, as well as using good quality Scottish ingredients.
"We can confirm the company is based in Aberdeen.
"Our logistics partner uses a hybrid vehicle to deliver them.
“Additionally, as part of the commitment to being a carbon-neutral event all food source and deliveries will be taken into the final total and offsetting calculations.”
A COP26 spokesperson said: "Sustainability is at the core of COP26.
"COP26 will be a carbon-neutral event and we will be the first COP to achieve validation under the internationally recognised standard, PAS2060."