Here's is the current legal definition of "margarine" in the EU (including the UK, as Brexit hasn't happened yet):
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2..."Products in the form of a solid, malleable emulsion, principally of the water-in-oil type, derived from solid and/or liquid vegetable and/or animal fats suitable for human consumption, with a milk-fat content of not more than 3 % or the fat content.
Margarine
The product obtained from vegetable and/or animal fats with a fat content of not less than 80 % but less than 90 %."
No mention of partial hydrogenation or trans-fats. The only reason UK spreads are not "margarine" is because they do no contain enough fat.