This actually happened on Wednesday but I'm still thinking about it and want to hear others' thoughts.
I go 2 junctions down the motorway, which is 4 lanes where I am, every day, and I also drive quite a bit for holidays etc. Where I join the motorway the slip road has 2 lanes - a really long one on the left and a very short one on the right that ends pretty abruptly. The slip-roads are up-hill, so if you use the short one, you can't really see what is coming up behind until you are very near its end. I always use the left one unless there is something in it going slowly, in which case I go past on the right. The traffic is always free-flowing when I join but people tend to move over to allow people on - with 4 lanes this is what you would expect.
Yesterday I used the right hand lane to join the motorway. Traffic was free-flowing and there were lorries in front then not a massive gap before more lorries coming up behind. I was going at about 50/60 I think. It was obviously going to be impossible to get on in front of the lorries ahead but those coming up behind were going at quite a speed so there was no room to get on in front of them, yet the slip road was running out. There was plenty of room for them to move to the right but they didn't. I had to slow right down and ended up on the diagonal white lines that divide the two slip lanes. As it passed, the lorry blew its horn even though I did not enter his lane at all. There was also a car coming up behind me, but that slowed right down behind me so it was ok.
It was just horrible - no room to the left or right and something coming behind, with no proper space to stop in either. Then the horn blowing as if I had done something wrong, but what? Surely the lorry coming up behind should have adjusted its speed or moved right? What else could I have done?