diff --git a/app/controllers/organisations_controller.rb b/app/controllers/organisations_controller.rb
index 6191f2129..6d9b1f4b5 100644
--- a/app/controllers/organisations_controller.rb
+++ b/app/controllers/organisations_controller.rb
@@ -117,7 +117,6 @@ class OrganisationsController < ApplicationController
   end
 
   def update
-    selected_rent_periods = rent_period_params[:rent_periods].compact_blank
     if (current_user.data_coordinator? && org_params[:active].nil?) || current_user.support?
       if @organisation.update(org_params)
         case org_params[:active]
@@ -136,11 +135,14 @@ class OrganisationsController < ApplicationController
         else
           flash[:notice] = I18n.t("organisation.updated")
         end
-        used_rent_periods = @organisation.lettings_logs.pluck(:period).uniq.compact.map(&:to_s)
-        rent_periods_to_delete = rent_period_params[:all_rent_periods] - selected_rent_periods - used_rent_periods
-        OrganisationRentPeriod.transaction do
-          selected_rent_periods.each { |period| OrganisationRentPeriod.create(organisation: @organisation, rent_period: period) }
-          OrganisationRentPeriod.where(organisation: @organisation, rent_period: rent_periods_to_delete).destroy_all
+        if rent_period_params[:rent_periods].present?
+          selected_rent_periods = rent_period_params[:rent_periods].compact_blank
+          used_rent_periods = @organisation.lettings_logs.pluck(:period).uniq.compact.map(&:to_s)
+          rent_periods_to_delete = rent_period_params[:all_rent_periods] - selected_rent_periods - used_rent_periods
+          OrganisationRentPeriod.transaction do
+            selected_rent_periods.each { |period| OrganisationRentPeriod.create(organisation: @organisation, rent_period: period) }
+            OrganisationRentPeriod.where(organisation: @organisation, rent_period: rent_periods_to_delete).destroy_all
+          end
         end
         redirect_to details_organisation_path(@organisation)
       else
diff --git a/app/helpers/organisations_helper.rb b/app/helpers/organisations_helper.rb
index a557f26d0..75d5869fa 100644
--- a/app/helpers/organisations_helper.rb
+++ b/app/helpers/organisations_helper.rb
@@ -19,7 +19,7 @@ module OrganisationsHelper
       { name: "Owns housing stock", value: organisation.holds_own_stock ? "Yes" : "No", editable: false },
       { name: "Rent periods", value: organisation.rent_period_labels, editable: true, format: :bullet },
       { name: "Data Sharing Agreement" },
-      { name: "Status", value: status_tag(organisation.status), editable: false },
+      { name: "Status", value: status_tag(organisation.status) + delete_organisation_text(organisation), editable: false },
     ]
   end
 
@@ -39,6 +39,12 @@ module OrganisationsHelper
     end
   end
 
+  def delete_organisation_text(organisation)
+    if organisation.active == false && current_user.support? && !OrganisationPolicy.new(current_user, organisation).delete?
+      "<div class=\"app-!-colour-muted\">This organisation was active in an open or editable collection year, and cannot be deleted.</div>".html_safe
+    end
+  end
+
   def rent_periods_with_checked_attr(checked_periods: nil)
     RentPeriod.rent_period_mappings.each_with_object({}) do |(period_code, period_value), result|
       result[period_code] = period_value.merge(checked: checked_periods.nil? || checked_periods.include?(period_code))
diff --git a/app/models/organisation.rb b/app/models/organisation.rb
index da041cd14..d56dd7afb 100644
--- a/app/models/organisation.rb
+++ b/app/models/organisation.rb
@@ -182,6 +182,8 @@ class Organisation < ApplicationRecord
   end
 
   def discard!
+    owned_schemes.each(&:discard!)
+    users.each(&:discard!)
     update!(discarded_at: Time.zone.now)
   end
 end
diff --git a/app/views/organisations/delete_confirmation.html.erb b/app/views/organisations/delete_confirmation.html.erb
index f0efe61bf..7ca97707b 100644
--- a/app/views/organisations/delete_confirmation.html.erb
+++ b/app/views/organisations/delete_confirmation.html.erb
@@ -5,7 +5,7 @@
 
 <div class="govuk-grid-row">
   <div class="govuk-grid-column-two-thirds-from-desktop">
-    <span class="govuk-caption-xl">Delete <%= @organisation.postcode %></span>
+    <span class="govuk-caption-xl">Delete <%= @organisation.name %></span>
     <h1 class="govuk-heading-xl">
       <%= content_for(:title) %>
     </h1>
diff --git a/spec/requests/organisations_controller_spec.rb b/spec/requests/organisations_controller_spec.rb
index dc8c08b52..11c7fbd84 100644
--- a/spec/requests/organisations_controller_spec.rb
+++ b/spec/requests/organisations_controller_spec.rb
@@ -1536,6 +1536,12 @@ RSpec.describe OrganisationsController, type: :request do
             expect(response).to have_http_status(:ok)
             expect(page).not_to have_link("Delete this organisation", href: "/organisations/#{organisation.id}/delete-confirmation")
           end
+
+          it "does not render informative text about deleting the organisation" do
+            follow_redirect!
+            expect(response).to have_http_status(:ok)
+            expect(page).not_to have_content("This organisation was active in an open or editable collection year, and cannot be deleted.")
+          end
         end
 
         context "with an inactive organisation" do
@@ -1546,6 +1552,44 @@ RSpec.describe OrganisationsController, type: :request do
             expect(response).to have_http_status(:ok)
             expect(page).to have_link("Delete this organisation", href: "/organisations/#{organisation.id}/delete-confirmation")
           end
+
+          context "and associated lettings logs in editable collection period" do
+            before do
+              create(:lettings_log, owning_organisation: organisation)
+              get "/organisations/#{organisation.id}"
+            end
+
+            it "does not render delete this organisation" do
+              follow_redirect!
+              expect(response).to have_http_status(:ok)
+              expect(page).not_to have_link("Delete this organisation", href: "/organisations/#{organisation.id}/delete-confirmation")
+            end
+
+            it "adds informative text about deleting the organisation" do
+              follow_redirect!
+              expect(response).to have_http_status(:ok)
+              expect(page).to have_content("This organisation was active in an open or editable collection year, and cannot be deleted.")
+            end
+          end
+
+          context "and associated sales logs in editable collection period" do
+            before do
+              create(:sales_log, owning_organisation: organisation)
+              get "/organisations/#{organisation.id}"
+            end
+
+            it "does not render delete this organisation" do
+              follow_redirect!
+              expect(response).to have_http_status(:ok)
+              expect(page).not_to have_link("Delete this organisation", href: "/organisations/#{organisation.id}/delete-confirmation")
+            end
+
+            it "adds informative text about deleting the organisation" do
+              follow_redirect!
+              expect(response).to have_http_status(:ok)
+              expect(page).to have_content("This organisation was active in an open or editable collection year, and cannot be deleted.")
+            end
+          end
         end
 
         context "with merged organisation" do
@@ -1749,15 +1793,26 @@ RSpec.describe OrganisationsController, type: :request do
 
       describe "#delete" do
         let(:organisation) { create(:organisation, active: false) }
+        let!(:org_user) { create(:user, active: false, organisation:) }
+        let!(:scheme) { create(:scheme, owning_organisation: organisation) }
+        let!(:location) { create(:location, scheme:) }
 
         before do
+          scheme.scheme_deactivation_periods << SchemeDeactivationPeriod.new(deactivation_date: Time.zone.yesterday)
+          location.location_deactivation_periods << LocationDeactivationPeriod.new(deactivation_date: Time.zone.yesterday)
           delete "/organisations/#{organisation.id}/delete"
         end
 
-        it "deletes the organisation" do
+        it "deletes the organisation and related resources" do
           organisation.reload
           expect(organisation.status).to eq(:deleted)
           expect(organisation.discarded_at).not_to be nil
+          expect(location.reload.status).to eq(:deleted)
+          expect(location.discarded_at).not_to be nil
+          expect(scheme.reload.status).to eq(:deleted)
+          expect(scheme.discarded_at).not_to be nil
+          expect(org_user.reload.status).to eq(:deleted)
+          expect(org_user.discarded_at).not_to be nil
         end
 
         it "redirects to the organisations list and displays a notice that the organisation has been deleted" do