What steps will reproduce the problem? >>>vatnumber.check_vies('GB100190874') True

>>> vatnumber.check_vat('GB100190874') False

>>> vatnumber.check_vat_gb('100190874') False

What is the expected output? What do you see instead? Since the VIES validates this VAT number, the "local" check should also pass it as True.

What version of the product are you using? On what operating system? Version 0.9 on Windows.

Looking at the pseudo-spec linked from wikipedia[1], it appears that the series for the 9755 checksum really starts at 100XXXXXX not at 101XXXXXX. Here is a patch that fixes the check and adds the relevant test sample.

[1] http://www.hmrc.gov.uk/ebu/developer-mins100309.htm - powerpoint slide 41

I have some comments on the patch. Could you submit a codereview using [1] And later could you follow this [2] for commit message.

[1] https://codereview.appspot.com/ [2] https://code.google.com/p/tryton/wiki/HowtoContribute

Here you go: http://codereview.appspot.com/5085044/

Updated patch following review comments

Applied in r7ad44efeb16a