Does anyone know what the orange flashing lights were over Durham City UK last night (5.2.12)?

This was lighting the whole sky up and had a rhythm to it - slowly getting brighter then slowly dimmer to eventually stopping for a few mins and then starting again. A lot of people saw this but have no idea where this was coming from. If anyone knows whether there was a light show etc please let me know ASAP! It seemed to be coming from Gilesgate/Durham City area. Thank you.