Copyright Aid

I have created and am the sole presenter of a rather unique IT education course and I have used a commercial IT training company to market it for about 10 years.
That company has recently decided to produce their own similar course and have adapted my promotional literature (the degree of direct plagiarism is huge,) and copied the unique and distinctive structure for their own product. Unlike most IT training course, this course is somewhat unique and recognisable with no other IT training company offering anything comparable.
Clearly I cannot stop a company from creating a similar product in an area they see as profitable, but the degree of plagiarism is so complete that a potential customer would scarcely recognise any difference between the two courses. Thus, shortly when they withdraw from selling my course, their new course will become a more or less identical replacement.
I was of the understanding that copyright would apply to items including promotional literature and also the intangible but vital structure of the course.
How should I try to protect my course with its "brand?"

Hi Frank,
You are certainly correct that any literature, including scripts and course materials you have produced, will be covered by copyright. The 'idea' of your course is not itself covered by copyright, but you imply that it is the way in which your course materials etc that have been copied very closely, so it seems that the expression or fixation of your idea may well have been infringed. What the law says is that infringement occurs where a work is substantially copied. That is a qualitative assessment and not necessarily a quantitative assessment, so if their course material captures the main essence of your work, even though they use only a small proportion of your actual wording, that may very well amount to infringement.
If you stand to lose out financially by this (as I assume you will) then it would be sensible to get some professional advice on what options are open to you. It may be that a letter before action drafted by a lawyer can pursuade this company to stop, but you will also need to explore how you can recover any losses (including legal costs) which you have already incurred.