Really differs from firm to firm but with how competitive things are, I expect that lots of firms expect at least a vacation scheme under your belt if you don't have a legal support role.
NRF was (before they axed direct TC completely) honest about this, they said they expected candidates to demonstrate some legal work experience to be considered for direct TC. However, this is definitely not a hard and fast rule. I know some people who have got direct TCs without any legal experience. But that's quite rare. I know the general vibe here is optimistic rather than realistic, but if you're at 0 legal work experience, I think it's better to try and gain some rather than spending time shooting for DTCs