Lumpy Box
The best as memory serves is of a plain white cardboard box about 12 by 9 by 2 inches which contained some or all or none of the following:
Half round of Spam sandwich,
Half round of 'Cheese' sandwich,
Usually a piece of Fruit and a sealed plastic container of Orange Squash.
Then, either;
Penguin Choc Bar, or
Apiece of Fruit Cake, or
Three Custard Creams.
These were issued on any flight or exercise of a duration where a main meal would not normally be taken. Included were Sim exercises, all training flights (MCT, CPT etc.) and route trips to say Northern Ireland, Scotland and Germany, - possibly even further.
Apart from keeping the chocy bars for the kiddies at home, little else was consumed. Even the Ground Crew turned their noses up at them, and I say that as one who started in the RAF as a Locking Apprentice.