The standard map of London senior school entry has two doors, with a later third. 11+ at the end of Year 6; 13+ at the end of Year 8, via the Common Entrance route or a school-specific paper; 16+ into the sixth form, for families moving from state to independent or between independents. Very little is said, in print, about the door in between.
It exists. Around fifteen London senior schools take meaningful numbers of pupils into Year 10 each September — a step often called 15+ entry, though several schools do not use that name. These are not residual places created by attrition. They are planned, registrar-managed, advertised (sometimes) in small print on an admissions page, and assessed through a process that shares only the broadest outline with the 11+.
Why it exists
Four pressures sustain the 15+ round. Prep school leavers who did not secure their first-choice 13+ place and moved elsewhere for Year 9, intending to reapply. Families relocating into London mid-GCSE. Pupils whose 13+ school has not worked out and who need a considered move before the GCSE cycle locks in. And a small but real number of families who wanted a state-school 11+ outcome, got one they were unhappy with by Year 9, and use the 15+ round as a reset.
Crucially, senior schools quietly value this cohort. A Year 10 entrant has more demonstrable academic record than a Year 7 candidate: the school has been at the pupil's current school long enough to produce a substantive reference and predicted GCSE grades. The 15+ round produces, in our experience, fewer poor fits than the 11+.
What the assessment looks like
Not the ISEB Common Pre-Test. 15+ entry is, almost everywhere, a bespoke assessment involving:
- English and Maths papers, pitched at top-of-Year-9 level and designed to test fit against the school's GCSE programme
- One or two interviews, typically with a senior teacher or deputy head rather than a purely admissions-facing registrar
- A close reading of the current school's reference, including behaviour and attendance
- A written piece — sometimes submitted in advance, sometimes sat on the day
Some schools add a science paper. Fewer add a modern language paper. The whole process is closer in tone to a sixth-form (16+) assessment than to an 11+ one.
"Our son had three 15+ assessments in four weeks. Two of them felt like interviews with someone who had already read the file. The 11+ industry hadn't prepared us for how different this round is." — composite, drawn from Mumsnet Secondary threads, late 2025
Which London schools run a genuine 15+ round
This is changeable year to year, and any list published in a journal piece will be partly out of date by September. The broad pattern, as of the 2025–26 cycle, is that the London 15+ schools cluster in three categories.
The larger, less-oversubscribed independents that use the round to steady the cohort into Year 10: Mill Hill, Alleyn's (small numbers), Latymer Upper (small numbers), and several others in the outer-London and semi-boarding belt. The Good Schools Guide's school-by-school coverage is, in our experience, the most reliable place to confirm current-year practice for each. [Good Schools Guide London coverage; individual school admissions pages]
Schools that run the round specifically for international families relocating mid-GCSE: Mill Hill again; several schools with strong boarding provision in commuter counties; schools with established pathways from specific international partner schools.
And schools that will, on enquiry, consider a 15+ entrant but do not advertise the round at all. This is a larger category than parents assume. The registrar-to-registrar conversation that happens when a pupil wishes to transfer between two independent schools in Year 9 often produces a place at a school whose public-facing page says only "occasional places, enquire directly." [City of London 10+ page for comparison; various school occasional places pages]
What to do if you are considering it
Three principles. First, start early: the 15+ round begins in the summer of Year 9 at several schools, and a January-of-Year-10 enquiry is usually too late for a clean September entry.
Second, be honest with the receiving registrar about the reason for the move. They will ask the current school anyway; a considered, calm account from the family usually sits better than a burnished one.
Third, do not overspend on preparation. The 15+ tutors who specialise in this round are, for the most part, strong; the tutors who will sell you an 11+-style fifty-hour package for a Year 9 child are working from the wrong template. Three or four sessions with a specialist, plus the pupil's own Year 9 work, is normally the right level of preparation for a top-London assessment.
The 15+ door is not a shortcut. It is a real, quieter round, running in parallel to the one everyone talks about — and for the right family in the wrong year, it is often the more workable route.
Sources: Good Schools Guide London coverage; City of London School 10+ admissions page (for comparison with 10+ occasional-place model); Mill Hill School admissions; various published occasional-places pages. Mumsnet fragments are composite and drawn from public Secondary-board threads, late 2025.