Article: https://olivertighe.co.uk/everything-you-need-to-know-about-agreements-in-principle-and-how-they-can-help-you/

An Agreement in Principle (AIP) is a document that outlines the terms of a potential mortgage agreement between a borrower and lender. It is not legally binding, but it does indicate the amount of money that the lender is willing to lend to the borrower.