I am a Scottish student and I was told that it was because, the past there were only two political parties in Britain, the torys and the whigs. The whigs had a more socialist political stance while the Torys were more conservative. In the house of commons (the British parliament) the party in government was on the right of the speaker and the Torys were in power for most of the time so those with a conservative viewpoint were right wing while the socialists were left.
Funny thing, when I was learning history I was taught it was because of the placement of the parties in the French parliament at the time of the French revolution.
These kind of questions should be posted in the forum “General Questions.”
Quand les talons claquent, l’esprit se vide.