I don't think technically that I was, but I'm sharing for thoughts.
I'm driving along a single carriageway 60mph stretch of road and there is a car in front doing about 40mph in front of me and so I get stuck behind him. A car arrives from behind me, and I can see that they are itching to overtake both of us.
We then enter a straight bit of road where I have a good long view where I see I can overtake safely. I indicate (for a few seconds) and move out, while the car behind me tries to overtake both me and the car in front. My car doesn't have the greatest acceleration and the car behind starts beeping at me. I manage to overtake and the car behind can't, so he goes back in line. I carry on my journey and I can see for a longtime that the overtaker to be is stuck behind the slow car.
Was I unreasonable to overtake, knowing there was a car with greater acceleration behind me who wanted to overtake both of us?