diff --git a/src/app/portfolio/[slug]/(portfolio)/page.tsx b/src/app/portfolio/[slug]/(portfolio)/page.tsx
index 4f9b0cde..d4514980 100644
--- a/src/app/portfolio/[slug]/(portfolio)/page.tsx
+++ b/src/app/portfolio/[slug]/(portfolio)/page.tsx
@@ -1,4 +1,6 @@
 import PropertyTable from "../components/PropertyTable";
+import UnmatchedProperties from "../components/UnmatchedProperties";
+import { getUnmatchedProperties } from "@/lib/properties/unmatched";
 
 export const revalidate = 60;
 
@@ -11,8 +13,11 @@ export default async function Page(props: {
   const params = await props.params;
   const portfolioId = params.slug;
 
+  const unmatched = await getUnmatchedProperties(portfolioId);
+
   return (
     <>
+      <UnmatchedProperties properties={unmatched} />
       <PropertyTable portfolioId={portfolioId} />
     </>
   );
diff --git a/src/app/portfolio/[slug]/components/UnmatchedProperties.tsx b/src/app/portfolio/[slug]/components/UnmatchedProperties.tsx
new file mode 100644
index 00000000..9d6ef33e
--- /dev/null
+++ b/src/app/portfolio/[slug]/components/UnmatchedProperties.tsx
@@ -0,0 +1,86 @@
+import {
+  ExclamationTriangleIcon,
+  MagnifyingGlassIcon,
+} from "@heroicons/react/24/outline";
+import type { UnmatchedProperty } from "@/lib/properties/unmatched";
+
+// The "needs attention" workspace that separates properties with no UPRN from
+// the matched portfolio table. Read-only for now; the per-row action is where
+// the advanced ARA search (edit address/postcode → search UPRN) will hang off.
+// Renders nothing when every property is matched, so a healthy portfolio stays
+// uncluttered.
+export default function UnmatchedProperties({
+  properties,
+}: {
+  properties: UnmatchedProperty[];
+}) {
+  if (properties.length === 0) return null;
+
+  const count = properties.length;
+
+  return (
+    <section
+      aria-label="Properties without a UPRN"
+      className="mb-6 overflow-hidden rounded-2xl border border-amber-200 bg-amber-50 shadow-sm"
+    >
+      <div className="flex items-start gap-3 border-b border-amber-100 px-6 py-4">
+        <ExclamationTriangleIcon className="mt-0.5 h-5 w-5 shrink-0 text-amber-500" />
+        <div className="min-w-0">
+          <div className="flex items-center gap-2">
+            <h2 className="text-sm font-bold text-amber-900">
+              Properties without a UPRN
+            </h2>
+            <span className="inline-flex items-center rounded-full bg-amber-200/70 px-2 py-0.5 text-xs font-semibold text-amber-800">
+              {count}
+            </span>
+          </div>
+          <p className="mt-0.5 max-w-xl text-xs text-amber-700">
+            {count === 1 ? "This property" : "These properties"} couldn&apos;t be
+            matched to an Ordnance Survey address automatically. Check the address
+            and postcode, then run an advanced search to find the right match.
+          </p>
+        </div>
+      </div>
+
+      <div className="bg-white">
+        <div className="grid grid-cols-12 gap-3 border-b border-gray-100 bg-gray-50/80 px-6 py-2 text-[11px] font-semibold uppercase tracking-wider text-gray-500">
+          <div className="col-span-6">Address</div>
+          <div className="col-span-3">Postcode</div>
+          <div className="col-span-3 text-right">Action</div>
+        </div>
+
+        <ul className="divide-y divide-gray-50">
+          {properties.map((p) => (
+            <li
+              key={p.id}
+              className="grid grid-cols-12 items-center gap-3 px-6 py-3"
+            >
+              <p
+                className="col-span-6 truncate text-sm text-gray-800"
+                title={p.address ?? undefined}
+              >
+                {p.address ?? (
+                  <span className="italic text-gray-400">No address</span>
+                )}
+              </p>
+              <p className="col-span-3 text-sm text-gray-600">
+                {p.postcode ?? <span className="text-gray-400">—</span>}
+              </p>
+              <div className="col-span-3 flex justify-end">
+                <button
+                  type="button"
+                  disabled
+                  title="Advanced ARA search — coming soon"
+                  className="inline-flex cursor-not-allowed items-center gap-1.5 rounded-lg border border-gray-200 bg-white px-3 py-1.5 text-xs font-semibold text-gray-400"
+                >
+                  <MagnifyingGlassIcon className="h-3.5 w-3.5" />
+                  Search UPRN
+                </button>
+              </div>
+            </li>
+          ))}
+        </ul>
+      </div>
+    </section>
+  );
+}
diff --git a/src/lib/properties/unmatched.ts b/src/lib/properties/unmatched.ts
new file mode 100644
index 00000000..9f8e6334
--- /dev/null
+++ b/src/lib/properties/unmatched.ts
@@ -0,0 +1,47 @@
+import { db } from "@/app/db/db";
+import { property } from "@/app/db/schema/property";
+import { and, asc, eq, isNull } from "drizzle-orm";
+
+export interface UnmatchedProperty {
+  id: string;
+  address: string | null;
+  postcode: string | null;
+}
+
+// Properties in a portfolio that have no UPRN — i.e. were never matched to an
+// Ordnance Survey address record. We surface these separately from the main
+// property table so the customer can correct the address/postcode and re-run
+// the address→UPRN search (the "advanced ARA search", wired up in a follow-up).
+// `markedForDeletion` rows are excluded so soft-deleted properties don't show.
+export async function getUnmatchedProperties(
+  portfolioId: string,
+): Promise<UnmatchedProperty[]> {
+  if (!/^\d+$/.test(portfolioId)) return [];
+  const pid = BigInt(portfolioId);
+
+  const rows = await db
+    .select({
+      id: property.id,
+      address: property.address,
+      postcode: property.postcode,
+      userInputtedAddress: property.userInputtedAddress,
+      userInputtedPostcode: property.userInputtedPostcode,
+    })
+    .from(property)
+    .where(
+      and(
+        eq(property.portfolioId, pid),
+        isNull(property.uprn),
+        eq(property.markedForDeletion, false),
+      ),
+    )
+    .orderBy(asc(property.address));
+
+  // Prefer the canonical address; fall back to whatever the user typed on
+  // import so the row is still identifiable while it awaits a match.
+  return rows.map((r) => ({
+    id: String(r.id),
+    address: r.address ?? r.userInputtedAddress ?? null,
+    postcode: r.postcode ?? r.userInputtedPostcode ?? null,
+  }));
+}