This happened to me about 20yrs ago. I was driving a Vauxhall Astra estate 1.7Td and I was towing a very large trailer which carried a two pole, all canvas marquee. The trailer was almost certainly overloaded and the lot was too heavy for the car. A mate of mine was in with me. The snake started on a long straight stretch, on the A1, on the way to Berwick on Tweed. I think we caught a side wind. Within seconds of the snake starting I could start to see the trailer appearing either side in my peripheral vision. All I thought at the time was if I put the brakes on this thing is going to push me around in a jack knife and we're gonners. I took my foot off the accelerator and fought the urge to brake, I'm pretty sure I feathered the accelerator occasionally as I was frightened we slowed down too fast and jack knifed. I've never watched a snaking trailer video before, so I reckon I was a second or two from disaster. I was very lucky.