YoungDan,

Been a while since I've done one (hoping I'm not going to need to in the near future either.

Basically I think you would need to include something along the lines of "...I therefore give you x weeks notice as per terms and conditions of employment and therefore to intend my final day of employment to x date..

Couple of reasonable examples here to help tailored to reasons for leaving:- http://www.i-resign.com/uk/letters/letters.asp?#No3

Useful to part on as good terms as possible as to ensure final pay is correct / P45 given (and not witheld!) and for future references

Otherwise just tell 'em to stick their job where the sun don't shine (only kidding, as ian said part on good terms with nothing derogatory in the letter)

Good luck with what you are moving onto do.

Lee.