No such office was provided for in the Government of Ireland Act 1920;[1] however, the Lord Lieutenant of Ireland,[2] as with governors-general in other Westminster systems such as in Canada, chose to appoint someone to head the executive even though no such post existed in statute law.

Nor, theoretically, was the executive committee and its prime minister responsible to the House of Commons of Northern Ireland.

In reality the governor chose the leader of the party with a majority in the House to form a government.

[5] The prime minister's residence from 1920 until 1922 was Cabin Hill, later to become the junior school for Campbell College.

In contrast with the Westminster-style system of the earlier Stormont government, the new Northern Ireland Executive operates on the principles of consociational democracy.