The code is a simple CAPCHA (“Completely Automated Public Turing test to tell Computers and Humans Apart”) – a simple way to verify that a real person is submitting the form and not a computer running an automatic submission program (aka a “bot”).

In recent years such programs have become very common on the internet. They aim to exploit vulnerable web sites, usually with the aim of hacking into the site, sending spam e-mails or promoting their own sites in the search engine listings.

Provided the web server and website are well secured and maintained, such attacks are ineffective but when applied to contact forms they are still a real irritation. So it’s becoming increasingly common to use a Captcha. My apologies for the inconvenience – it’s just a sad reality of life on the internet.