Last mile of pregnancy and I have the worst backache conceivable - any tips on what I can do to make it better?

You can try applying a warm towel or one of those warm water bottles where the ache is most intense. These can alleviate backaches by improving blood flow to your aching muscles, thus bringing some much needed relief.

It could be back labour - means you are entering labour soon. Happens to 25% of pregnant women! Try soaking in a hot water tub

thanks