Function CheckPostcode(ByVal postcode)

        Dim OutCode As String
        Dim InCode As String

        'Set case and remove embedded spaces
        postcode = UCase(Replace(postcode, " ", ""))

        'Check the length of the postcode
        If (Len(postcode) < 5) Or (Len(postcode) > 7) Then
            'Invalid length (must be between 5 and 7 characters long)
            PostcodeOk = False
        Else
            'Length OK, so split the postcode and proceed with the validation
            OutCode = Left(postcode, Len(postcode) - 3)
            InCode = Right(postcode, 3)

            If (Not InCode Like "#[A-Z][A-Z]") Then
                'Invalid incode (must be of the format "NAA")
                PostcodeOk = False

            ElseIf (Mid(InCode, 2, 1) Like "[C,I,K,M,O,V]") Or (Mid(InCode, 3, 1) Like "[C,I,K,M,O,V]") Then
                'Invalid incode (2nd or 3rd characters cannot be C, I, K, M, O or V)
                PostcodeOk = False

            ElseIf (Left(OutCode, 1) Like "[Q,V,X]") Or (Mid(OutCode, 2, 1) Like "[J,I,Z]") Then
                'Invalid outcode (1st character cannot be Q, V or X, second cannot be J, I or Z)
                PostcodeOk = False

            ElseIf (Len(OutCode) = 2) And (Not OutCode Like "[A-Z]#") Then
                'Invalid outcode (2 character outcode must be of the format "AN")
                PostcodeOk = False

            ElseIf (Len(OutCode) = 3) And (Not OutCode Like "[A-Z]##") And (Not OutCode Like "[A-Z]#[A-Z]") And (Not OutCode Like "[A-Z][A-Z]#") Then
                'Invalid outcode (3 character outcode must be of the format "ANN", "ANA" or "AAN")
                PostcodeOk = False

            ElseIf (Len(OutCode) = 4) And (Not OutCode Like "[A-Z][A-Z]##") And (Not OutCode Like "[A-Z][A-Z]#[A-Z]") Then
                'Invalid outcode (4 character outcode must be of the format "AANN" or "AANA")
                PostcodeOk = False

            Else
                'Valid postcode
                PostcodeOk = True

            End If
        End If
        Return PostcodeOk
    End Function