How to prevent stop back button calling myurl?mode=del&customer=name

Hi, I have a form where customer names are displayed as a hyperlink to allow editing, deletion etc..., e.g. http://mysite.com/main/customer.php?mode=del&customer=name I click on the "delete customer X" link and everything works as it should and X gets deleted. If I then click the back button on my browser, I recall this url and it, not-surprisingly :-), tries to repeat the same operation. Is there anyway to prevent this? I have tried many header options for disabling caching but this is not the HTML I am trying to stop being cached, it is the URL itself. This is not an uncommon way to provide actions to users, so somebody somewhere must have worked out how do this - surely ;-) It would apply to CGI, ASP, ColdFusion and any other serverside language as well, it's just that I'm using PHP. I have tried this with IE5 and Navigator 4.73 Thanks in advance for any advice you may have Alan