I went and looked it up…
Guidance on using cling film safely
The FSA’s advice is that not every type of cling film is suitable for all uses. To protect the quality and taste of food and make sure cling film is used correctly, it is important not to:
use cling film where it could melt into the food – eg in conventional ovens or with pots and pans on cooker hobs
allow cling film to touch the food when re-heating or cooking it in a microwave oven
use cling film in contact with high fat foods unless the manufacturer’s advice says it is suitable for this
High fat foods include:
some types of cheese
raw meats with a layer of fat
fried meats
pastry products
cakes with butter icing or chocolate coatings
How plastic food contact materials are regulated
European Commission Regulation 10/2011 controls the substances used in plastic food contact materials and sets out conditions for using them. The directive applies throughout Europe and its rules are included in UK food law. Independent expert committees have examined the plasticisers used in cling film. Where necessary, restrictions have been introduced to protect public health.
The Food Contact Materials Team can provide more information about the safety of cling film used in the food industry. You can contact them by email at FoodContactMaterial@foodstandards.gsi.gov.uk. Alternatively, you can call the Food Standards Agency Food Contact Materials Team Helpline on Tel 020 7276 8555.
So you’re probably fine with cold sandwiches assuming they’re not high fat…