If people have pots of established lilies, then it's not too early to see visible growth. I've just taken these two snaps, this morning...
This is a pot of established lilies which have overwintered in a cold greenhouse...
The pot just below is outside, and has been outside all Winter...
The slim shoots may be coming from bulblets not far beneath the surface.
If people have lilies growing in open soil then you need to be aware that the plants are awake, and any slugs that are about will be making a meal of those little shoots, if you're not careful.
I'm in Warwickshire. I would guess that things are more advanced in some other areas.