Hi Mark
Basically all packaged food has a "use-by" date and tins and pouched meals are around 5 years - BUT THIS CAN VARY WITH STORAGE CONDITIONS!
Most tinned or pouched meals will last indefinately as long as the packaging is not compromised and I have eaten many a rat pack meal older than 5 years old with no ill effects and no noticable deterioration of the food quality. I have also had "in date" rat pack meals that, having had pin hole punctures of the packaging, have rotted and could have killed me if I had tried eating the stuff....If the bag is inflated the meal is rotting (like a botulism blown tin can) if the meal stinks it is rotted, if it looks fine, smells fine and has been boiled in the bag foe 10mins then - bon apetite!
Oh - use your own judgement as I take no responsibility for any deaths by poisoning that can be atributed to eating out of date packaged food .... what you put in your mouth and belly is your own affair!
Jack Horner brand plum pies may not be the best food for you at the moment......
See you in Llandysul soon?
John