What Is Copyright?
The purpose of the law of copyright universally, is to grant those who create, produce or author works the exclusive right to do certain acts in relation to their works. This bundle of rights is exclusive to them and others can only perform these acts with the copyright holder's authority and consent or, of course, when copyright has expired. This exclusive bundle of rights, which is collectively known as "copyright", is a right in property, which is as valuable and palpable (even though copyright technically represents intangible or incorporeal property) as a piece of land (even though it is not real property) or a car!
Historically, copyright is the consequence of the Gutenburg press of four centuries ago and was utilised initially to protect printed matter but has been liberally amended over the last century to include films, sound recordings, photographs, broadcasts and cable programmes.
In so far as the UK Copyright, Designs and Patents Act 1988 (as amended) ('CDPA') is concerned, copyright is the exclusive right given to authors, composers, publishers, playwrights or distributors to exclusive publication, production, sale or distribution of original literary, dramatic, musical or artistic works. Any other person who does any of these acts in respect of a substantial portion of a work, whether directly or indirectly, without the consent, permission or licence of the copyright holder infringes copyright and is liable to damages, injunctions, account of profits and delivery up.
The Idea/Expression Dichotomy
Traditionally, it is necessary, in order to get copyright protection, to reduce an idea to a material form or express it in such terms. As Peterson J said in London Press Ltd v University Tutorial Press Ltd  2 Ch 601: 'Copyright Acts are not concerned with the originality of ideas, but with expression of thought'. Indeed, section 3(2) of the CDPA implies this by providing that copyright 'does not subsist in a literary, dramatic or musical work unless and until it is recorded, in writing or otherwise'.
Thus, clearly, copyright protects expressions rather than ideas. So while an idea in a person's mind, even if it is uttered to someone who does not do anymore than just hear it, is never copyrightable, it does become so when it is reduced into or expressed in some material form. So a story in your head, however rattling good a yarn it may be, cannot obtain copyright protection, even if you have told it to your children or grandchildren, until and unless it is put on "paper"! Thus, the spoken word, without more, is incompatible to the subsistence of copyright.
However, recently some have challenged this traditional view - which appears to have received continuous support from the courts over the centuries - by arguing that 'the law ought to recognise the potential for copyright to subsist in any perceptible expression emanating from the intellect of a person and intended to appeal to the aesthetic sense or intellect of others, regardless of the expression's materiality.'
What Does Copyright Protect?
Pursuant to section 1(1) of the CDPA, copyright subsists in:
original literary work
original dramatic work
original musical work
original artistic work
the typographical arrangement of published editions
This means that the protection of copyright is extended to these nine categories authors' and entrepreneurial works.
What Do They Mean?
Literary Work means any work, other than a dramatic or musical work, which is written, spoken or sung and includes a table or compilation, computer program and preparatory design material for a computer program...