diff --git a/app/models/saved_scenario.rb b/app/models/saved_scenario.rb
index 816a1ee..b787c78 100644
--- a/app/models/saved_scenario.rb
+++ b/app/models/saved_scenario.rb
@@ -14,6 +14,9 @@ class SavedScenario < ApplicationRecord
   validates :title,       presence: true
   validates :end_year,    presence: true
   validates :area_code,   presence: true
+  validates :version, presence: true, inclusion: {
+    in: Version.all
+  }
 
   serialize :scenario_id_history, coder: YAML, type: Array
 end
diff --git a/app/models/version.rb b/app/models/version.rb
new file mode 100644
index 0000000..d3a3bd3
--- /dev/null
+++ b/app/models/version.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+# A valid version of the ETM
+class Version
+  LIST = %i[
+    latest
+  ].freeze
+
+  # All available versions. Uses ActiveRecord syntax 'all' to
+  # make future porting to db easier
+  def self.all
+    LIST
+  end
+end
diff --git a/db/migrate/20241014102534_create_saved_scenarios.rb b/db/migrate/20241014102534_create_saved_scenarios.rb
index 2fbfc0b..7cee9b7 100644
--- a/db/migrate/20241014102534_create_saved_scenarios.rb
+++ b/db/migrate/20241014102534_create_saved_scenarios.rb
@@ -5,6 +5,7 @@ def change
       t.text :scenario_id_history
       t.string :title, null: false
       t.text :description
+      t.string :version, default: 'latest'
       t.string :area_code, null: false
       t.integer :end_year, null: false
       t.boolean :private, default: false
diff --git a/db/schema.rb b/db/schema.rb
index 9321b35..01fb7b9 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -16,6 +16,7 @@
     t.text "scenario_id_history"
     t.string "title", null: false
     t.text "description"
+    t.string "version", default: "latest"
     t.string "area_code", null: false
     t.integer "end_year", null: false
     t.boolean "private", default: false