What aircraft has a single constant orange light? I live under a fly path in Oldham near Manchester and I see planes passing by every day/night as they approach the airport. However today around 21.20 I have seen something different too.

A plane just passed above our house to start its approach to Manchester then when it was further away roughly above Ashton-under-Lyne I noticed a contrast single orange light passing above the house.

It was somewhat higher than the passenger planes around this area and it's travelled with constant great speed. I followed with my eyes until it's disappeared on the horizon above the peak district (took about 1.5-2 minutes). It's travelled in a direction about SSE (roughly towards London). I couldn't find anything on the Internet suggesting anything flying with constant orange light. BTW it had no sound whatsoever and it wasn't showing up on flight radar either as I checked that straight away. I do not drink and do not smoke funny things. Any idea what this could be?
From your description it sounds more like the International Space Station than an aircraft. That looks like a small orange or yellow light because it's the reflection of the sunlight For that reason you're most likely to see it in the hour or two after sunset, and it's clearly visible with the naked eye in good visibility. It's much higher than aircraft and takes about 90 seconds to travel horizon to horizon. Obviously you won't hear it or see anything on aircraft tracking sites.

That said, ymb1 suggested looking at this ISS tracker site. Assuming your 2120 was in British Summer Time (UTC+1), the ISS would have been somewhere over the South Pacific Ocean at that time, which would rule it out.