Some spammer has hijacked my name, which is not a run of the mill name, and is sending emails to my contacts. The email addresses used are not mine. Is there anything I can do to stop it?
It is most likely that your email account has been hacked at some point and your contacts addresses were harvested.
The spammer can now send emails to the contacts any time he/she chooses. The spammer will be "spoofing" your email address to make it appear that the emails are coming from you in an attempt to make the emails appear genuine.
All you can do is stop using your email address and advise your contacts that you are no longer using the email address ad that they should treat any emails purporting to be from it as spam and delete it immediately.
See links about spoofing.
Thanks for your prompt response. A pity nothing can be done to disable those sender email addresses.
As quickly as they could be taken down a new one would appear. They are generated in the thousands if not hundreds of thousands.