Did the British enslave the Irish at any point in history?

The Irish were never treated as chattel slaves as were Africans. Poor Irish left Britain and worked as indentured servants where, after a period of servitude, they gained their independence. Some masters were unfair and broke the arrangements of the contract, and many Irish died due to bad conditions in the New World such as disease and poor sanitation. The British also deported Irish political prisoners to the New World and Australia, where many were forced to work on sugar plantations. Some children were exported to the New World in order to "retrain" them in the Protestant way of life and to avoid having one more poor person in the workhouse.
While some may claim that the Irish were indeed slaves, there are differences between indentured servitude and chattel slavery. Indentured servants eventually gained their freedom and their children were free, whereas chattel slavery was generational. Even though life was hard for the Irish and many were treated brutally, it was still better than slavery in that servitude, for the Irish, was a temporary event.