SIGHTING REPORT UFO sighting at Mottingham, SE London

Round in shape comprising of a yellow light surrounded by an orange coloured light. Couldn't see shape of the object that the light was coming from.

Light appeared from behind my house. I watched it move quickly across the sky in a straight line, seemingly making no noise (an aeroplane was also going over at the time and although I couldn't see it I could hear it's path as it travelled across the sky, with this object I could see it but not hear it at all). The sky was quite cloudy but the light was very bright.
Once in front of my house it seemed to jerk quickly to the left then stop still. Whilst watching the light seemed to dim, as if the object was travelling away from me, straight up into the sky. I watched it dim until it disappeared completely.

Didn't appear to be a plane as there was only the one light as opposed to an aeroplane having one on each wing, that flash! Also no apparent engine noise, which also rules out a helicopter.
Not sure what it was but it really did seem to go straight up into the sky until it couldn't be seen any more. A man walking past also stopped to watch it as it was very unusual.
I have never seen or reported anything like this before so please let me know if anyone reports anything similar.