Did you complain to Asda at the time? I would imagine they would probably give you a token sum as a gesture if goodwill but nothing massive. See this:
"Foreign bodies
When it comes to finding something in a food product you've bought, it's always best to return the item to the shop where it was purchased. Take with you the product, foreign body found and your receipt if you still have it. Ask to speak to the manager.
You can insist on a replacement or if appropriate, a refund as the shop has supplied you with something which isn't of satisfactory quality and has, therefore, broken its contract with you (Sale of Goods Act 1979, section 14).
This applies even though the shop itself is unlikely to have been at fault. If you've eaten part of the foreign body and become ill as a result, you could also recover compensation from the shop for illness and lost wages. Do be aware that the shop may want to take the product from you for testing, so it maybe worth taking photographic evidence as proof."
So basically, unless you ate it and were off work ill and lost wages as a result, I doubt you will get compensation.