David Blunkett has had a cheque 'washed' and the amounts/payee replaced with new details. The original story was in the Telegraph. This nicely illustrates the advantages of using a 'bulletproof' ink, such as 'Noodlers'. I ran my own tests on this ink here. I use three different noodlers at the moment, Walnut (not bulletproof), Legal Lapis and Black.
The Black and Legal Lapis are both pretty permanent once on paper. Indeed, there is a reward to anyone who can remove Noodlers Black without damaging the paper (i.e. to show that it's susceptible to the type of fraud used against Blunkett)
Just to make it crystal clear, Identity Cards would not have prevented this theft! Using a non washable ink would have done!