How do you stop excel removing leading zeros?

I need the leading zero to be in the cell when you click on it. Formatting the cell using special or custom are not suitable as they display the leading zero but when you click on the cell it does not contain a leading zero. Formatting the cell for text or putting an apostraphy before the 0 are not suitable either. This is because the file has to be imported into an application that will not accept formats of this type. Is there any other way?

Exactly what does the other application require? The other application can't use a number, but it also can't use a number stored as text or other text input? Can it use the result of a formula (=TEXT(1,"000"))?

Can you give more information? How does the data get from Excel to the other application? What data type/format does the other application require?

You can create a custome format for this. Go under Format> Cells> Custom. Enter '000#' ( or ever many '0' are needed). This will still keep the entery formatted as a number, not text.