According to journalist Sam Wallace, it wasn't just a few. Appalling behavour really, and with Brexit happening it will get worse. Will never understand such people, utterly pathetic really.
They've always been atrocious, and not a small minority either. I used to go to the very occasional England game with a couple of mates who supported different club sides, we'd rarely go to the see each other's teams and it always seemed relatively easy to get England home tickets. We stopped going after the England-Wales game at Old Trafford in 04.
The Welsh were out in force, seemed prepared for the kind of chants they'd receive as loads of them had blow up sheep they were waving. They were chanting stuff about being sheep shaggers themselves before the game kicked off, clearly unperturbed by the jibe. That didn't stop the English fans around me starting a sheep shagger chant every 5 minutes. Each time it started you could see the Welsh fans laughing at it and waving in our general direction. Which of course annoyed the English fans because it wasn't intended to be "banter", they were doing it to try and piss the Welsh off. A few minutes later they'd try it again, as if the Welsh fans had changed their minds in mean time. It was embarrassing to start with, but by half time we were ready to walk out because it was so tedious, we felt like idiots just being associated with them, and seemingly had nothing remotely in common with anyone else in our section. By about 65 minutes there were lads pointing out individuals in the Wales section and making throat slitting gestures. A bunch behind me started up a "no surrender" chant because they "wanted to practise it before the Northern Ireland game" that was coming up next.
We left shortly after.
Never again. Such a humourless, vindictive bunch. Barely interested in the game, they just wanted to abuse people.