Public Sub InvertColours()

'       This subroutine inverts the colours of the background and foreground colours.

'       It is recommended that you define a marco to execute this, either that or
'       set it as a right-click option.

Dim c As Excel.Range
Dim tempInt As Long
For Each c In Selection
    If c.Interior.Color = xlNone Then
        c.Interior.Color = vbBlack
        c.Font.Color = RGB(255, 255, 255)
    Else
        tempInt = c.Font.Color
        c.Font.Color = c.Interior.Color
        c.Interior.Color = tempInt
    End If
    If c.Interior.Color = RGB(255, 255, 255) Then c.Interior.Color = xlNone
Next c
End Sub