Here's a link to a sound file of the half hour radio episode first aired over fifty years ago on 4 November 1956.
Tony Hancock receives a tax demand for £14 12s 3d re ten years' back tax. He refuses to pay as that represents 50% of his income over the period! (Even fifty years ago this would have been a tiny amount!) so he goes to see the Inspector - played by Kenneth Williams.
The inspector tells Hancock that he can't just pay the outstanding tax, they have to haggle a bit. He also says that most people ignore his letters. Once they've been ignored twice he ignores the taxpayers! He also recommends that Hancock should go to see a Chartered Accountant "you'll probably get away with it then!". Hancock takes his advice but the accountant turns out to be a crooked Sid James and mayhem ensues.