SIGHTING REPORT UFO sighting at On the M4 Motorway

I think was about the size of like a 737 mabey a bit smaller, i couldnt see the shape very well, i know it did not have wings, there was odd lights all around the sides of it, it a really strange read swirly pulsating light on the back i think it was the back anyway coz what i thought was the front had these 2 bright white lights side by side.

The cloud was quite low over the motorway and it was and i saw this odd thing in the sky from quite a way off towards us, right at the edge of the cloud cover above kind of peeping out but could see all these lights, it moved in a southerly direction slowly sort of turning and then over the fields beside us, coming out of the cloud cover slightly. then the thing which really clinched it for me as being something inexpilcable was it shot down then up very prescisly and roboticly only about 40 feet or something and it kind of glided away. really weird, there must have been others that saw it as the motorway was very busy.