This was an email reply to a query, it has been confirmed by a phone call:
SUBJECT McDonald’s customer services department ref: 1136229.
Thank you for your email to Steve Easterbrook regarding our fillet o fish product, which has been passed for my attention.
I can confirm that the fillet o fish we offer in our restaurants in the UK are not halal. In fact i can confirm that we do not offer any menu items in our restaurants that are halal products.
I trust the above information is of help.
Regards
Joe Cuffaro
Customer services manager
McDonald’s customer services department
tel:0870524462.
Filet of Fish at Mac Donalds- No Halal at Mac Dee’s
Karimah's Cuisina Quranic Cooking 
if you open a business, customer service is always a must. –
<a href="Our own blog site
http://www.foodsupplementdigest.com/l-tyrosine-side-effects/
They can’t claim to be halal unless endorsed by HMC or the like. So no, they wouldn’t say that their food was halal. Had you asked if it was suitable for vegetarians then you may have got a different answer. I’m not saying that they are permissible or not to eat as Muslims, but ask the right questions.