Margaret Thatcher was dragged into a 1989 row over where to locate a new Mid-Antrim hospital, newly-released Government files show.
Plans had already been drawn up for a 600-bed hospital in Antrim, but Doctor Ian Paisley lobbied strongly for Ballymena.
Writing to the former prime minister, the late North Antrim MP argued against locating the hospital in Antrim.
He told her it "will not realise the objective of a modern efficient service readily available to all".
Replying for Mrs Thatcher , Secretary of State Tom King suggested meeting Dr Paisley to discuss his concerns.
Ballymena 'lost out' with the eventual construction of Antrim Area Hospital.