There seems to be a spate of hacking going on.
My primary @btinternet.com account stopped working about half an hour ago, password didn't work, went through 'forgot my password' procedure (but I hadn't forgotten it...) and that didn't work as the security answers were 'wrong'.
Rang them ..... Indian call centre ....... transferred from the Broadband support number to the Premium Mail number, both exceptionally helpful, friendly, and solved the problem very quickly. I know people like to moan about these call centres but, in this case at least, 10/10. If anyone from BT reads this ..... thank you.