It seems that the might Google are having some server issues today. Although I can access my GMail account new emails are not coming in. I have tested my pop3 accounts and these are working OK, so it is definately a Google problem. This is the first time I have seen such a problem with GMail, however I am sure that they are working to resolve the issue.
After I have informed clients of the problem I shall see what information is available on google.com and/or their blogspot status alerts.