As per the 24-hour cancellation policy, an additional fee will not apply if the ticket is cancelled within the first 24 hours of booking. British Airways allows you to cancel your reservation within the leniency period and get a full refund. This policy applies to all types of fares. You can cancel your ticket online.
https://flightcancellationpoli....cy.com/british-airwa

British Airways Cancellation Policy | Cancel Flight

Get all information About British Airways Cancellation Policy .And Get back your refund if you can cancel your flight within a day of booking,