Depends which specialty, some are desperate for consultants and others aren't. In Pathology for example, there was an open spot a few years ago that let people run up through the grades unobstructed because there happened to be a three or four year run without many applicants. Equally, I know SpRs in their late-thirties and early-forties in specialties like Neuro or the very competitive surgical jobs. In general though, as a student joining between 18-21, you'll be in your mid-thirties when you reach consultant.