The plane on which British Airways has chosen to showcase its special ‘BA Better World’ livery is an Airbus A320neo that bears the registration G-TTNA. According to data from ch-aviation.com, this is one of 15 A320neos in the BA fleet. The oneworld founding member also has a further seven on order. These 180-seat twin jets have an average age of 2.3 years.
Source "Simply flying"