The Tax man is after me !!!

I completed my tax return on time and had it with the IR by 31st January deadline. They have sent me a bill which is quite stern in its tone. They are asking that I pay my tax bill without delay, and if there is a delay there will be serious consequences. In the final paragraph of said tome they even mention imprisonment!! Having tangled with the tax man before I really don't want to get into trouble with him again!! :). Today I am going to write out a cheque and post it immediately as I really don't want to incur the wrath of the grey men in grey suits. The amount of my tax bill is £1.60. I don't think I can afford it. What am I going to do?