something is wrong with my turnips

Your help please;  something is eating the roots of my turnips.

A couple of weeks ago i noticed that a few of my turnips had keeled over. When I looked they had no central root left to hold them into the soil. I have just discovered the culprit; a small brown worm like thing with a viscious looking head.

Any ideas what they are and what I should do. The same raised bed has mooli and parsnips growing. Are they in danger too?

I killed the one I found; it was crawling through the roots that were left.

Next one i will photo. Sorry, I should have thought.

I have looked through pests on the internet but couldn't find it. It definitely didn't have legs and it had sort of tiny pincers on its head which it was constantly moving (the head that is). It was 2-3cm slim and completely brown.

Husband says he found one on the floor after he had brought some turnips in. He didnt associate it with the turnips and thought that perhaps the cat needed worming!