Morrell was a farmer from near Coleraine, and was active in the Ulster Unionist Party (UUP). He was elected to Coleraine Rural District Council in 1962, then Londonderry County Council in 1969. In 1973, he was elected to Coleraine District Council, and also to the Northern Ireland Assembly from the Londonderry constituency. Although he was a supporter of UUP leader Brian Faulkner, Morrell refused to sign a pledge to support a relevant White Paper, as asked., but became Deputy-leader of the Ulster Unionist Party, under Brian Faulkner, his wife becoming Vice President of Ulster Women's Unionist Association under Lucy Faulkner.
Faulkner appointed Morrell as Minister of Agriculture when the Northern Ireland Executive was created. After Sunningdale when Faulkner resigned after losing a vote on the Agreement in the Unionist Council, he joined Faulkner's new Unionist Party of Northern Ireland, becoming deputy leader of the party. The Executive fell as a result of the Ulster Workers' Strike in May 1974. However, Morrell lost his seat in Londonderry in the 1975 elections to the Northern Ireland Constitutional Convention. Morrell did not defend his seat in the Northern Ireland local elections, 1977, and resigned as deputy leader of the party in 1978, to focus on farming and developing the Voluntary Housing Movement in Northern Ireland
- Biographies of Prominent People - 'M', CAIN Web Service
- Northern Ireland Assembly Elections 1973, Northern Ireland Elections
- Londonderry 1973-1982, Northern Ireland Elections