Flashing lights static in the sky over North Sea

Object had no sound but flashed red blue yellow and white lights- maintained height and posistion with high powered lens took many photo's and enhanced images with lightroom to get detail.stayed in same place for 1 and half hours at least.
Photo's were taken showing ships below on the horizon to give scale and size of object.There were fighter MOD flights but were finished by 20.00 at a nearby test range where target practice takes place -mainly in the daylight hours.