Direct comparisons of the carbon footprint of different meat is quite difficult. Meat from beef cows has a far higher footprint than from dairy cows. Beef from cows grazing on what used to be virgin rainforest has an even higher footprint. The food miles involved are actually only a very tiny part of the over footprint but buying local helps your local economy and you know the provenance of the animals. The UK has some of the strictest animal welfare laws but this does tend to make UK meat more expensive.