diff --git a/app/models/scheme.rb b/app/models/scheme.rb
index 6d3524723..2c73acc06 100644
--- a/app/models/scheme.rb
+++ b/app/models/scheme.rb
@@ -103,6 +103,22 @@ class Scheme < ApplicationRecord
 
   scope :visible, -> { where(discarded_at: nil) }
 
+  scope :duplicate_sets, lambda {
+    scope = visible
+    .group(*DUPLICATE_SCHEME_ATTRIBUTES)
+    .where.not(scheme_type: nil)
+    .where.not(registered_under_care_act: nil)
+    .where.not(primary_client_group: nil)
+    .where.not(has_other_client_group: nil)
+    .where.not(secondary_client_group: nil).or(where(has_other_client_group: 0))
+    .where.not(support_type: nil)
+    .where.not(intended_stay: nil)
+    .having(
+      "COUNT(*) > 1",
+    )
+    scope.pluck("ARRAY_AGG(id)")
+  }
+
   validate :validate_confirmed
   validate :validate_owning_organisation
 
@@ -192,6 +208,8 @@ class Scheme < ApplicationRecord
     "Missing": "X",
   }.freeze
 
+  DUPLICATE_SCHEME_ATTRIBUTES = %w[scheme_type registered_under_care_act primary_client_group secondary_client_group has_other_client_group support_type intended_stay].freeze
+
   enum arrangement_type: ARRANGEMENT_TYPE, _suffix: true
 
   def self.find_by_id_on_multiple_fields(scheme_id, location_id)
diff --git a/spec/factories/scheme.rb b/spec/factories/scheme.rb
index 7983bfa0a..5f4ad30bc 100644
--- a/spec/factories/scheme.rb
+++ b/spec/factories/scheme.rb
@@ -32,5 +32,14 @@ FactoryBot.define do
       confirmed { false }
       support_type { nil }
     end
+    trait :duplicate do
+      scheme_type { 4 }
+      registered_under_care_act { 1 }
+      primary_client_group { "O" }
+      secondary_client_group { "H" }
+      has_other_client_group { 1 }
+      support_type { 2 }
+      intended_stay { "M" }
+    end
   end
 end
diff --git a/spec/models/scheme_spec.rb b/spec/models/scheme_spec.rb
index 9b3db15a4..277ebf65b 100644
--- a/spec/models/scheme_spec.rb
+++ b/spec/models/scheme_spec.rb
@@ -208,6 +208,125 @@ RSpec.describe Scheme, type: :model do
           end
         end
       end
+
+      context "when getting list of duplicate schemes" do
+        let(:organisation) { create(:organisation) }
+        let!(:scheme) { create(:scheme, :duplicate, owning_organisation: organisation) }
+        let!(:duplicate_scheme) { create(:scheme, :duplicate, owning_organisation: organisation) }
+        let(:duplicate_sets) { described_class.duplicate_sets }
+
+        it "returns a list of duplicates in the same organisation" do
+          expect(duplicate_sets.count).to eq(1)
+          expect(duplicate_sets.first).to contain_exactly(scheme.id, duplicate_scheme.id)
+        end
+
+        context "when there is a deleted duplicate scheme" do
+          before do
+            create(:scheme, :duplicate, discarded_at: Time.zone.now)
+          end
+
+          it "does not return the deleted scheme as a duplicate" do
+            expect(duplicate_sets.count).to eq(1)
+            expect(duplicate_sets.first).to contain_exactly(scheme.id, duplicate_scheme.id)
+          end
+        end
+
+        context "when there is a scheme with a different scheme_type" do
+          before do
+            create(:scheme, :duplicate, scheme_type: 7)
+          end
+
+          it "does not return a scheme with a different scheme_type as a duplicate" do
+            expect(duplicate_sets.count).to eq(1)
+            expect(duplicate_sets.first).to contain_exactly(scheme.id, duplicate_scheme.id)
+          end
+        end
+
+        context "when there is a scheme with a different registered_under_care_act" do
+          before do
+            create(:scheme, :duplicate, registered_under_care_act: 2)
+          end
+
+          it "does not return a scheme with a different registered_under_care_act as a duplicate" do
+            expect(duplicate_sets.count).to eq(1)
+            expect(duplicate_sets.first).to contain_exactly(scheme.id, duplicate_scheme.id)
+          end
+        end
+
+        context "when there is a scheme with a different primary_client_group" do
+          before do
+            create(:scheme, :duplicate, primary_client_group: "H")
+          end
+
+          it "does not return a scheme with a different primary_client_group as a duplicate" do
+            expect(duplicate_sets.count).to eq(1)
+            expect(duplicate_sets.first).to contain_exactly(scheme.id, duplicate_scheme.id)
+          end
+        end
+
+        context "when there is a scheme with a different secondary_client_group" do
+          before do
+            create(:scheme, :duplicate, secondary_client_group: "O")
+          end
+
+          it "does not return a scheme with a different secondary_client_group as a duplicate" do
+            expect(duplicate_sets.count).to eq(1)
+            expect(duplicate_sets.first).to contain_exactly(scheme.id, duplicate_scheme.id)
+          end
+        end
+
+        context "when there is a scheme with a different has_other_client_group" do
+          before do
+            create(:scheme, :duplicate, has_other_client_group: 0)
+          end
+
+          it "does not return a scheme with a different has_other_client_group as a duplicate" do
+            expect(duplicate_sets.count).to eq(1)
+            expect(duplicate_sets.first).to contain_exactly(scheme.id, duplicate_scheme.id)
+          end
+        end
+
+        context "when there is a scheme with a different support_type" do
+          before do
+            create(:scheme, :duplicate, support_type: 4)
+          end
+
+          it "does not return a scheme with a different support_type as a duplicate" do
+            expect(duplicate_sets.count).to eq(1)
+            expect(duplicate_sets.first).to contain_exactly(scheme.id, duplicate_scheme.id)
+          end
+        end
+
+        context "when there is a scheme with a different intended_stay" do
+          before do
+            create(:scheme, :duplicate, intended_stay: "P")
+          end
+
+          it "does not return a scheme with a different intended_stay as a duplicate" do
+            expect(duplicate_sets.count).to eq(1)
+            expect(duplicate_sets.first).to contain_exactly(scheme.id, duplicate_scheme.id)
+          end
+        end
+
+        context "when there is a scheme with nil values for duplicate check fields" do
+          let!(:scheme) { build(:scheme, :duplicate, owning_organisation: organisation, scheme_type: nil, registered_under_care_act: nil, primary_client_group: nil, secondary_client_group: nil, has_other_client_group: nil, support_type: nil, intended_stay: nil).save(validate: false) }
+          let!(:duplicate_scheme) { build(:scheme, :duplicate, owning_organisation: organisation, scheme_type: nil, registered_under_care_act: nil, primary_client_group: nil, secondary_client_group: nil, has_other_client_group: nil, support_type: nil, intended_stay: nil).save(validate: false) }
+
+          it "does not return a scheme with nil values as a duplicate" do
+            expect(duplicate_sets).to be_empty
+          end
+        end
+
+        context "when there are duplicate schemes without secondary client group" do
+          let!(:scheme) { create(:scheme, :duplicate, owning_organisation: organisation, secondary_client_group: nil, has_other_client_group: 0) }
+          let!(:duplicate_scheme) { create(:scheme, :duplicate, owning_organisation: organisation, secondary_client_group: nil, has_other_client_group: 0) }
+
+          it "does not returns the duplicates" do
+            expect(duplicate_sets.count).to eq(1)
+            expect(duplicate_sets.first).to contain_exactly(scheme.id, duplicate_scheme.id)
+          end
+        end
+      end
     end
   end