The sixth-form decision, as most London families rehearse it in kitchen conversations, is a binary: A-Levels or the International Baccalaureate Diploma. In practice, the choice is rarely that symmetrical. Most London senior schools now offer one or the other, not both; the schools that offer both are doing so less evenly than their prospectuses suggest; and the Cambridge Pre-U, a third option that had a ten-year run as an alternative to A-Levels at a handful of independents, has effectively ended — the final Pre-U examinations were sat in summer 2023, after Cambridge Assessment confirmed it would be withdrawn. [Cambridge Assessment withdrawal notice, 2021; various school announcements, 2021–23]
What remains, at the London schools most families are choosing between, is a clearer division than you might expect.
The A-Level schools
The largest group. Westminster, St Paul's, Highgate, City of London, Dulwich, Alleyn's, Latymer Upper, Eton (boarding, but commonly on London shortlists), and several others run A-Levels as the sole sixth-form route. Westminster's own published admissions materials set out A-Level as its sixth-form programme, with an option for International A-Levels in some subjects where departments judge it a better fit. [Westminster School, Sixth Form Subject Choices]
For a strong academic child with a clear subject-depth preference — typically the mathematician, or the classicist, or the physicist who wants two years of further maths — A-Levels remain a natural fit. A-Levels also remain the most legible currency for UK university admissions: tutors read them faster than they read IB transcripts, which is not the same as saying they value them more.
The IB schools
A smaller, more deliberate group. Sevenoaks went all-IB more than a decade ago and has not looked back. King's College School Wimbledon runs both, with roughly 40 per cent of its sixth form on the IB and 60 per cent on A-Levels — one of very few London senior schools that genuinely offers parity of provision. The Sunday Times Parent Power guide named King's its International Baccalaureate School of the Year in 2025, with an average IB score of 41.25 and 62 per cent of Higher Level subjects awarded the top grade of 7. [King's College School Wimbledon; Good Schools Guide; Sunday Times Parent Power 2025]
Other genuinely IB-strong London schools — Southbank International, ACS Cobham (outside London, but on many London lists), a handful of state IB providers — serve a family whose child wants breadth, whose second language is real, and whose university horizon may not be in the UK. The IB's appeal to universities in the US, Continental Europe and East Asia remains measurably stronger than its appeal to Russell Group admissions tutors; that gap has narrowed since 2020 but has not closed.
The mixed picture
A small number of London schools continue to offer both. King's Wimbledon is the most visible example. In several others, the balance has shifted materially in favour of A-Levels over the last five years, with IB cohorts shrinking to a dozen or fewer pupils. That shrinkage matters: an IB cohort of eight is not the same experience as a cohort of eighty, and the subject combinations available at smaller schools become very constrained.
Parents considering a mixed-offer school should ask directly: how many pupils are currently in each Year 12 and Year 13 cohort in each programme; which Higher Level IB subjects are actually running this year; and whether the school has a stated view on maintaining both routes for the long term. The answers vary considerably.
"We were told the IB cohort would be 'around twenty'. In the event it was fourteen, and the HL economics option we had been counting on did not run. We stayed — but it was a scramble." — composite, drawn from Mumsnet Sixth Form threads, autumn 2025
The Cambridge Pre-U footnote
For completeness: the Cambridge Pre-U — a linear, A-Level-equivalent qualification that a handful of independents (Charterhouse, Winchester, Oundle, and others) used in parallel with A-Levels for a decade — was withdrawn by Cambridge Assessment in 2021 and ran its final cohort through 2023. Any school still publishing a Pre-U option in a 2026 prospectus is working from a stale brochure. [Cambridge Assessment International Education, withdrawal notice, 2021]
The useful question for a Year 10 or Year 11 family is therefore narrower than the one parents often pose. It is not "A-Level or IB", in the abstract. It is "which school — with which programme, at which cohort size, with which Higher Level subjects actually running in 2026–27 — fits my child." Almost all the interesting information sits in that second question.
Sources: Westminster School published subject choices; King's College School Wimbledon sixth-form curriculum; Cambridge Assessment International Education withdrawal notice (Cambridge Pre-U); Good Schools Guide; Sunday Times Parent Power 2025.