Regular Expression Validator seems to be wrong!

[Edward]

I have the following control on my page:

<asp:regularexpressionvalidator id="RegularExpressionValidator1"
style="Z-INDEX: 104; LEFT: 355px; POSITION: absolute; TOP: 28px"
runat="server" Width="131px" Height="10px" ErrorMessage="The Postcode
is not in the correct format" ValidationExpression="
^([A-PR-UWYZ0-9][A-HK-Y0-9][AEHMNPRTVXY0-9]?[ABEHMNPRVWXY0-9]?
{1,2}[0-9][ABD-HJLN-UW-Z]{2}|GIR 0AA)$"
ControlToValidate="txtPostCode"></asp:regularexpressionvalidator>

The Validation Expression comes from here:

http://www.regexlib.com/RETester.aspx?regexp_id=260

If I enter a valid postcode in regexlib's tester, I get a match.

If I enter a valid postcode in "txtPostCode", I get an error message.

Help!

Edward