I am afraid that this blog has once again been under a spam attack all day, in which spammers are trying to post spurious comments at a rate of about one every minute.
I have therefore had to limit comments to those who are already recognised by the blog, or who log in to make their comment. I am very sorry that this will make it more difficult to add a comment for some. Once the attack has gone away, I hope to be able to ease that restriction again.
Please don’t let it inhibit your use of the blog, or making comments.
The avalanche of spam comments appears to have stopped at last, and these restrictions have now been removed. Please comment freely!