Diamond, Partially Selective and Bilateral Schools Explained (2026-27)

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"Partially selective," "bilateral" and "diamond model" are three of the most confused terms in English school admissions, and only two of them actually describe a way of selecting pupils. A partially selective school, such as Dame Alice Owen's School in Hertfordshire, reserves a fixed percentage of its intake — currently up to 32.5% by academic ability — for the highest-scoring applicants and teaches everyone together once admitted. A bilateral school, such as Ashlawn School in Warwickshire, instead runs two separate teaching streams, selective and non-selective, inside one school. A "diamond model" school is something else entirely: an independent school's teaching structure, with no connection to state-school selection at all. This guide explains each model precisely, names the real schools and local authorities that use them, and gives the exact 2026-27 place numbers straight from each school's own published admissions policy.

What Is a Partially Selective School in England?

A partially selective school is a state-funded secondary school that selects a proportion of its intake by academic ability or a named aptitude — general ability, music, sport, modern languages, art, design technology or dance — while admitting the rest of its pupils through the ordinary criteria used by any non-selective school (distance, sibling links, looked-after-child status, and so on). Crucially, once admitted, pupils are not streamed by how they got in: a partially selective school teaches its selective and non-selective intake as one comprehensive cohort.

This arrangement exists only because of a grandfather clause. The School Standards and Framework Act 1998 explicitly stopped any new school from introducing selective admissions, but it protected schools that already selected part of their intake before 1997 from having to give the practice up, provided the proportion selected never exceeds its 1997 level. A small number of schools that converted to grant-maintained status between 1993 and 1997 — when government circulars permitted selection of up to 10%, later expanded — locked in selection quotas as high as 50% before the window closed. Roughly three dozen schools nationally still operate under this protection today, concentrated in Hertfordshire, Kent, Essex, Dorset, Wandsworth, Sutton, Croydon, Barnet and a handful of other authorities. None exist in Scotland, Wales or Northern Ireland, which never had the same 1997 cut-off point built into their admissions law.

Named current examples include Dame Alice Owen's School (Hertfordshire), Queens' School in Bushey (Hertfordshire), Homewood School in Tenterden (Kent), and Burntwood School in Wandsworth — each with its own percentage, set out below with sourced 2026-27 or 2027-28 figures.

What Is a Bilateral School — and How Is It Different From Partial Selection?

A bilateral school also selects part of its intake by test, but the resemblance to a partially selective school stops there. Where a partially selective school blends its selective and non-selective admissions into one teaching cohort, a bilateral school keeps the two streams separate — one grammar-style selective stream and one non-selective stream — taught within the same site, under the same headteacher and the same uniform. The model has its roots in the 1960s and 1970s Tripartite System, when some sparsely populated areas found it uneconomical to run a separate grammar school and secondary modern, and instead combined the two into a single bilateral institution.

Ashlawn School in Rugby, Warwickshire, is a clear working example. Its own 2026-2027 admissions policy states plainly that "Ashlawn School is a publicly funded, bilateral school" that allocates up to 56 of its 256 places by selection: 31 places to applicants who meet the school's Automatic Qualifying Score (208, most recently confirmed for 2022 entry) in an 11+ test of verbal reasoning, non-verbal reasoning and numeracy, and a further 25 places to the highest-scoring applicants in a separate modern languages aptitude test. The remaining places are filled through the school's standard non-selective oversubscription criteria. Other current bilateral schools include Reading Girls' School (Berkshire), The Howard School (Medway), St Bernard's High School and St Thomas More High School (both Southend-on-Sea, sharing the Consortium of Selective Schools in Essex test), King Edward VI Humanities College (Lincolnshire) and Westlands School (Torbay).

What Is a "Diamond Model" School? (And Why It Isn't a Selective Admissions Model)

Because "diamond" sounds like it could describe another shape of academic banding, it's a genuinely common mix-up — but a diamond model school has no connection whatsoever to selective intake, grammar-style testing, or any of the mechanisms above. The term describes a teaching structure used by a number of English independent (fee-paying) schools: pupils are taught in mixed classes through the early years and again in a joint sixth form, but taught separately by gender for academic lessons during Years 7 to 11 — the "waist" of the diamond shape the name refers to. New Hall School in Essex (now part of Saint Anselm's family of Catholic schools) is generally credited with originating the approach in the 1990s. Schools currently running variations of the diamond model include Berkhamsted School and Haberdashers' Monmouth Schools, Brentwood School, Clifton High School, Dame Allan's Schools, and The Grammar School at Leeds; a related "diamond edge" variant applies gender separation only to specific subjects (commonly STEM) rather than the whole timetable.

None of these are state grammar schools. None use an 11+ test, a qualifying score, or a fixed percentage quota of any kind — admission to an independent school follows that school's own entrance assessment and is unrelated to the diamond structure, which is purely about how pupils are grouped for lessons once admitted. If your starting question was "is my child's school a selective diamond school?", the honest answer is that the two ideas do not overlap: a diamond model school's selectivity, where it exists, comes from being an independent school with its own entrance exam and fees — not from any diamond-specific admissions mechanism.

How Many Places Are Selective? Real Numbers From Named Schools' Current Admissions Policies

Percentages quoted for partially selective and bilateral schools change from year to year as each school runs its own annual admissions consultation, so the only reliable figures are the ones published in each school's determined arrangements for a specific entry year. The table below draws directly from each school's own policy document or the relevant local authority's published admissions booklet, not from a secondary aggregator, and is year-stamped so you can check it against the current version on the school's own website before applying.

Two patterns stand out. First, Hertfordshire's partially selective schools sit at the high end (32.5%-35% general ability, plus additional music and sport quotas), while Kent's Homewood School sits much lower at 20% — there is no single national percentage, and each authority's schools have arrived at very different figures through decades of separate local consultations. Second, none of these schools publish a fixed pass mark: Queens' School's policy states explicitly that places go to applicants "strictly in descending order of candidates' standardised test scores" until the quota is filled, so the effective cut-off moves up or down every year depending on how the whole cohort performs.

Fully Selective vs Partially Selective vs Bilateral vs Diamond vs Comprehensive: What's the Difference?

With five different labels in circulation, it helps to see them side by side against the two questions that actually distinguish them: does the school select any of its intake by ability or aptitude, and if so, are selected and non-selected pupils taught separately once admitted?

It's worth noting a sixth, related but distinct concept: "fair banding," used by some fully comprehensive local authorities (Wandsworth, Lambeth and Camden among them) to test every applicant and place them into ability bands so each school in the area gets a representative spread of abilities — not to select an academically selective minority. Banding is not selection in the sense used above: every child who sits a fair banding test is guaranteed a place somewhere in the scheme, just not necessarily at their first-choice school. We cover fair banding separately in our guide to borough banding tests in Wandsworth, Lambeth and Camden, because it is a genuinely different mechanism from the fixed-quota selective models covered here, even though the two are frequently confused in parent forums.

How Did Partially Selective and Bilateral Schools Survive the End of the Grammar School System?

Most of England replaced its grammar-and-secondary-modern Tripartite System with comprehensive schools between the late 1960s and the 1970s. A small number of local authorities never fully completed the transition, and some schools that had converted to grant-maintained status kept a degree of academic selection when grant-maintained status was abolished in 1998. The School Standards and Framework Act 1998 is the specific piece of legislation that determines what survived: Section 100 protects any selection arrangement that existed immediately before the Act, capped at its 1997 level, and Section 102 separately permits up to 10% selection by aptitude for a specialist subject at any school with a specialist designation, regardless of history.

The high-water mark for this kind of selection was 1997 itself: government circulars issued in 1993 and expanded in 1996 had allowed grant-maintained schools to introduce selection, and by the time the window closed, more than 40 schools nationally were selecting up to 50% of their intake by ability. A 2006 amendment then tightened the rules again, requiring every partially selective school to use the lowest percentage it had used at any point since 1997 — not simply its 1997 figure — which is why several Hertfordshire schools had to reduce their general ability quota from 35% down to 25% for a period. Schools adjudicators, appointed under the same legislative framework, continue to rule on individual objections to selective admissions arrangements each year, and a small number of schools have had their selective quotas reduced or challenged through this process since.

Which Local Authorities Use Partially Selective and Bilateral Admissions?

Partially selective and bilateral schools are heavily concentrated in specific local authorities rather than spread evenly across England. Hertfordshire has the largest concentration of any single county, including the South West Herts Consortium (Parmiter's School, Queens' School, Rickmansworth School, St Clement Danes School and both Watford Grammar Schools) plus several non-consortium partially selective schools such as Dame Alice Owen's School and Bishop's Stortford High School. Greater London has a cluster across Wandsworth (Burntwood School, Graveney School, Chestnut Grove School), Sutton (Greenshaw High School, part of the Sutton SET testing group), Barnet (Mill Hill County High School) and Croydon (Shirley High School). Essex runs several partially selective and bilateral schools through its own Consortium of Selective Schools in Essex (CSSE) 11+ test, including Shoeburyness High School, St Bernard's High School and St Thomas More High School. Kent's Homewood School in Tenterden is a partially selective outlier inside a county otherwise built almost entirely around fully selective grammar schools such as Weald of Kent Grammar School — worth noting because Kent's grammar schools, including Weald of Kent, are fully selective and use the standard Kent Test (plus, for Weald of Kent from the 2026 entry cycle, an additional school-set test alongside it), not a partial-selection or bilateral model. Smaller numbers of partially selective schools also operate in Dorset, Nottingham, Liverpool and the West Midlands. For a fuller picture of how selective admissions work across specific counties, see our Hertfordshire 11+ guide and Kent 11+ guide.

How Do You Apply to a Partially Selective or Bilateral School?

The process runs on two parallel tracks that both need to be completed. First, every family applies through their home local authority's standard secondary transfer common application form (CAF), due by 31 October in Year 6, listing up to six schools in order of preference — this is exactly the same form used to apply to any comprehensive school. Second, and separately, if any school on your list uses academic, music, sport, subject or language selection, you must register for that school's own test or audition, usually earlier in the autumn term and sometimes as early as June of Year 6 for schools that run their own assessment day. Ashlawn School's policy, for example, requires the 11+ test registration to be completed months ahead of the CAF deadline; Queens' School similarly runs its assessment tests separately from the Hertfordshire common application process.

If you miss a school's separate selective-test deadline, you can usually still name the school on your council application, but you will only be considered for its non-selective places — which, since even the most selective schools on this list cap selection at 45%, still represents the majority of every school's intake. Conversely, sitting and qualifying on a school's selective test does not guarantee a place if the school is oversubscribed even within its selective quota: Queens' School and Dame Alice Owen's School, for instance, both allocate their selective places in strict descending order of test score, so a qualifying score in one year may not be sufficient in a more competitive year.

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