Although cream tea may occasionally refer to tea with cream added*, it usually refers to a type of afternoon tea meal. Cream tea is a lighter afternoon tea meal, more like a snack. It's made up of scones and tea. Condiments like jam, Devon cream, butter and lemon curd may also be served for the scones, and milk and sugar are optional for the tea.
By their nature, most cream tea meals are vegetarian. If you omit the milk and Devon cream and prepare vegan scones, then cream tea can easily become a vegan meal. (Seems like a bit of an oxymoron, but it's true!)
* Cream is not traditionally added to British tea. Milk is the preferred tea additive.