According to:
http://www.ttgmedia.com/news/news/br...-mistake-17460

A WDL Aviation spokesperson added: “We are working closely with the authorities to investigate how the obviously unfortunate mix-up of flight schedules could occur.“At no time has the safety of passengers been compromised. We flew the five passengers on the flight with number BA3271 to Dusseldorf after the involuntary stopover in Edinburgh.”