It might be three cornered garlic/leek - Allium triquetrum. If it is, I’ve read it can be a thug - it would normally flower a little later but I guess where it’s been mild some things are popping up early
An invasive species brought over to the UK from the Mediterranean, it is an offence under Schedule 9 of the Wildlife and Countryside Act in England and Wales to plant or otherwise cause to grow this species in the wild.
https://www.wildfooduk.com › three...
I found this too Andrea and Rich @richard.spicer.7906
Cutting the flower heads off when they start to die back will greatly reduce its spread providing you do it before seeds ripen. It will still be getting bigger by bulb offsets but the seeds will be what makes it spread further afield - possibly how it arrived in your garden - as Jane said it’s a thug. Maybe dig it up and keep it in a pot, or a sunken pot, so at least the bulblets don’t get spread either while you dig around it?