Image copyright MOrrisons

Morrisons is recalling its "Traditional Chicken and Mushroom Pie" from sale because a small number of packs do not contain that pie, but a fish pie.

The fish pie contains fish and mustard which are not mentioned on the label.

As a result, the Food Standards Agency says the supermarket's pies are a possible health risk for anyone with an allergy to mustard and/or fish.

It says that those bought in error should be returned to the store from where they were bought.

The product at the heart of the mix-up is the Morrisons "Traditional Chicken & Mushroom Pie" in the 400g packs, with a use-by date of 4 December 2017.

Morrisons, the UK's fourth-biggest supermarket chain, has apologised for the error and is also contacting allergy support organisations, which will tell their members about the recall.

Mustard allergies are rare in the UK, although more common in Spain and France. The effects for those with a mustard intolerance are anaphylactic shock, more commonly provoked by peanuts.

Notices explaining why the pies are being withdrawn are being placed in Morrisons' stores. No other Morrisons products are known to be affected.

The FSA issues food and allergy alerts whenever necessary - typically several a week. The more serious reasons include finding pieces of plastic in a food stuff, or the presence of health-threatening bacteria, such as botulinum, Listeria or Campylobacter.

But in a recent inversion of the Morrisons mishap, the FSA issued a recall alert in September on behalf of rival supermarket Asda, which had found that some pies labelled as fish pies were in fact chicken and bacon ones, containing mustard.