In principle I agree with previous posts on this.

However, just to answer your specific question please be informed that IF you DO bring ANY food back from Pinas, and you're unsure if it's allowed or not, then always declare to a UKBA officer in the RED channel (or on the red point phone).
If your products are illegal, they will be seized and destroyed, but you will face no further action (such as a fine or prosecution).

If you go through the green channel and UKBA Officers find any undeclared and illegal items, you will face a significantly long delay, the goods will be seized and destroyed, and you MAY face a penalty fine or formal prosecution.

According to European Commission Regulation 206/2009, personal imports of meat and dairy products are not permitted – it doesn’t even matter if the products are vacuum-packed, tinned or in a sealed packet.
So no corned beef.

Fish/Fishery products are allowed into UK from Pinas, even dried fish!
So tins of tuna would be OK. Provided it did not contain any other ingredients from the non-permitted list.

As others have said it really does seem pointless to use up your baggage allowances on tins of tuna.