Born in Solihull, the son of Thomas Forster by his marriage to Edna Russell, Forster was educated at the town's Tudor Grange Grammar School. He stated in the House of Lords on 8 February 2016 that he had spent his gap year making Land Rover Defenders and was auto-enrolled into the TGWU. He studied at Merton College, Oxford, where he graduated with a Bachelor of Arts (BA) in chemistry, promoted to Master of Arts (MA Oxon) in 1973. At the University of Edinburgh, he graduated as a Bachelor of Divinity (BD) in theology in 1977 and as a Doctor of Philosophy in 1985.
