Criminal hackers have reportedly accessed the data of nearly nine million customers of three major United Kingdom airports.

According to BBC News, hackers were able to access customer contact details, vehicle registrations and postcodes from customers of Manchester Airports Group (MAG), which owns Manchester, East Midlands and London Stansted airports. MAG said that the hackers also demanded a ransom fee for the return of the data, which the company refused to pay. 

MAG said that it became aware of the hack on August 25, and that it "immediately contained the risk" once it was discovered. The company is now working with specialized advisors to better protect its systems moving forward. 

The firm said that passenger safety and aviation security data was not compromised in the cybersecurity incident, and that the systems that were exposed did not contain customer bank or payment deals. Rather, the majority of data that was accessed was limited to customer email addresses stemming from WiFi signups at airport terminals. Vehicle registration data was also accessed from booking systems for parking lots, airport lounges and fast-track services.