i got email off them and not been with them for 5 years reads as follows
Dear Customer,
As part of our security measure, we regularly screen activity in the Halifax Plc system. You received this message due to an issue on your account.
Due to unusual number of invalid login attempts on your account, we have reason to believe there might be security breach on your account.
Your account requires extra verification process to ensure your identity and your account security.
Click on Sign in to Secure online Banking to continue to the verification process and ensure your account security.
Halifax Online Helpdesk