Bracken Cave by Denis Bushell

On reaching a very tight mud slope with the low stream imminently at the bottom I knew I had to tackle this problem on my back. I elected to enter the slope head first knowing there might no be a lot of airspace when reaching the stream and if it went progress would be easier then feet first. Three metres down the slope I abruptly jammed. I could not progress. I beckoned to Fay to pull my feet and I would shuffle my shoulders. This was the answer. On looking back down I could not understand how I jammed and decided to have  a second attempt...