Just saw this on RTT and wondered what the error actually was?
http://www.realtimetrains.co.uk/train/G71897/2016/06/21/advanced
http://www.realtimetrains.co.uk/train/G71897/2016/06/21/advanced
2K53 1105 Welwyn Garden City to Moorgate
Great Northern service
This service was cancelled throughout due to a planning error (TI).