Thanks for that, unfortunately I don't think that will help in my particular
circumstances.
This is for a time sheet that will be used by lots of people, most of whom
will be Excel novices. They will need to be able to enter, for example
-01:00, if they have worked 1 hour less than their conditioned hours.
I think I need some way of formatting the cell that that either positive or
negative time values can be entered.
Unfortunatley it is also not a cell that could be populated with a formula.
Any suggestions?