When you sign the petition on line, you will receive an e-mail from the office of the PM. You must not delete this e-mail immediately (which most of us might be inclined to do without reading because anything from No10 makes me ) because it contains a link back to the petition site which you must click in order to validate that it was you that signed the petition electronically.

If you did delete without validating, either (but not both):
1. Recover from your "Deleted Mail" folder and action as above; or
2. Try signing the petition again.
Let Her Fly