On my way to pick up MrG from work I have to drive around a very large roundabout with several traffic light points. I usually tackle it safely and with my wits about me, picking the right lane etc etc. When Mr G does it, he sometimes pulls out into smaller gaps than I would choose, because he can get up speed from a standing start that I wouldn't dare do yet. I am not old-lady slow, but I am still improving my driving and gaining experience. Yesterday it was really busy and had a number of fairly careless drivers, taking risks and speeding/revving. While I was waiting to go onto the roundabout the traffic from the right (from two different sets of traffic lights) was fast and heavy. As the lights changed, cars came really quickly and I waited for a decent space. There wasn't a space, and soon the lights had changed to let the other lane go - all were very fast and some had obviously gone on amber because they were on us almost instantly. A car behind me sounded its horn, despite the fact that there was steady oncoming traffic going right across my lane. I stayed put until it was safe to pull out. Then, when I saw the lights change again, I pulled out, despite noticing a dark car absolutely belting towards me, must have done really fast start from standing at the lights. Instead of putting the accelerator to the floor and zooming out, I felt panicky and slowed somewhat to a steady speed, relying on the other car to slow and let me into the right lane. I know it wasn't good manners, but once committed I had to keep going. Thought if I was slowish, then it might be inconvenient, but not too dangerous. I'm always having to give way to other cars in similar situation and it's part of manouevring on a roundabout like this, I reckon.Bearing in mind too, that this car had only travelled a few yards from a standstill at the lights. He must have decided to teach me a lesson or something, because he continued really, really fast and despite my signalling right, he somehow squeezed past me on the inside of the roundabout as I went round. Cut me up drastically. I don't know how it didn't hit me. If I had speeded up even slightly, it would have clipped my front right and it would have been a bad smash considering the speed it was going at. He wasn't even in the right lane, since he cut across me to leave at the next exit. Another car, travelling equally speedily, came round on my left and sounded a long horn as he swerved round on the other side of me. I could have been sandwiched between the two of them. It was only a few yards anyway to another set of traffic lights and I was composed enough to be in the right lane and take the next exit as normal. I arrived at husband's workplace with horrible thoughts of what might have happened. I told him what had happened (mistake) and he offered to drive home. I said I would prefer to drive so that I didn't make a big thing of it and could overcome it straight away. I drove home smoothly and safely as usual, but with a lecture all the way home from the passenger seat. Kept having flashbacks last night and first thing this morning. Resolved to learn from the experience, rather than let it upset me, but still keep thinking I could have been smashed to oblivion!