Isn't she lovely.....pity about the name

This is Hermodactylus tuberosus, formerly Iris tuberosa - and commonly known as the Snakes-head iris or the Widow iris.

Just going over now, we have several clumps naturalising in the garden.

The blue-green leaves start to appear in December and this year the flowers were out in January, slightly earlier than usual.  Here they are growing beneath two silver birch trees which means they have more shade than is probably ideal.
The flowers are quite short-lived but stunning while they are around and very welcome as a prelude to spring.