After contesting Liverpool Wavertree in 1964, Thorne was Member of Parliament for Preston South from February 1974 to 1983, and, after boundary changes, for Preston from 1983 until his retirement in 1987.
After contesting Liverpool Wavertree in 1964, Thorne was elected as Member of Parliament for Preston South from February 1974 to 1983 and then for Preston from 1983 until his retirement in 1987.