Leek flower. Oops?

This year is the first time I've tried to grow leeks (Musselburgh)

I'm pretty happy with the way they've come on, but one of them has developed what appears to be a flower head (see pic, just above the middle.)

I've snipped it off, but this isn't supposed to happen in their first year, (is it?  )

Not supposed to.

It's bolted!

Hope it's just the one then otherwise leek-wise I'll be completely bolted and screwed!