The history of turn-key starts in the UK with Ian Duncan Wallace, QC redefining legislation in the early 1980s.
He cites "...a contract where the essential design emanates from, or is supplied by, the Contractor and not the owner, so that the legal responsibility for the design, suitability and performance of the work after completion will be made to rest....with the contractor....'Turnkey' is treated as merely signifying the design responsibility as the contractor's"
This means that a turnkey project is a type of construction that is supplied to the buyer as a completed product. It refers to something that is ready for immediate use.
In Australia, it is told that AV Jennings were the first to implement this type of product to consumers in Melbourne offering a 'turn the key and walk in' product, as a response to adaptation of the changing market.