That's right! This is Yew. Yew trees are extremely toxic to horses and all grazing animals. Yew poisoning is the commonest form of animal poisoning. All parts (dead or living) are poisonous, especially the leaves. Yew contains an alkyloid that depresses the action of the heart.

Yew is sometimes used in hedges or as an individual ornamental plant, e.g. be careful what you put in the show ring! Yew needles are greenish-yellow on the under surface and have no white stripes.