diff --git a/pkg/runner/aggregate_sender.go b/pkg/runner/aggregate_sender.go
index 440835e..3d86f13 100644
--- a/pkg/runner/aggregate_sender.go
+++ b/pkg/runner/aggregate_sender.go
@@ -138,17 +138,13 @@ func (as aggregateSender) send(fileName string, ts time.Time, duration time.Dura
 	if err != nil {
 		return fmt.Errorf("sendAggregateFile: unable to send request, elapsed time %s: %w", elapsedTime, err)
 	}
+	defer res.Body.Close()
 
 	bodyData, err := io.ReadAll(res.Body)
 	if err != nil {
 		return fmt.Errorf("sendAggregateFile: unable to read response body: %w", err)
 	}
 
-	err = res.Body.Close()
-	if err != nil {
-		return fmt.Errorf("sendAggregateFile: unable to close HTTP body: %w", err)
-	}
-
 	if res.StatusCode != http.StatusCreated {
 		as.log.Error(string(bodyData))
 		return fmt.Errorf("sendAggregateFile: unexpected status code: %d", res.StatusCode)
diff --git a/pkg/runner/aggregate_sender_test.go b/pkg/runner/aggregate_sender_test.go
new file mode 100644
index 0000000..a8407ad
--- /dev/null
+++ b/pkg/runner/aggregate_sender_test.go
@@ -0,0 +1,95 @@
+package runner
+
+import (
+	"crypto/ed25519"
+	"crypto/rand"
+	"io"
+	"log/slog"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/lestrrat-go/jwx/v2/jwa"
+	"github.com/lestrrat-go/jwx/v2/jwk"
+)
+
+func TestAggregateSenderClosesBodyOnReadError(t *testing.T) {
+	closed := make(chan struct{})
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if _, err := io.Copy(io.Discard, r.Body); err != nil {
+			t.Errorf("draining request body: %s", err)
+			return
+		}
+
+		hj, ok := w.(http.Hijacker)
+		if !ok {
+			t.Error("ResponseWriter does not implement Hijacker")
+			return
+		}
+		conn, buf, err := hj.Hijack()
+		if err != nil {
+			t.Errorf("Hijack: %s", err)
+			return
+		}
+		_, _ = buf.WriteString("HTTP/1.1 201 Created\r\nContent-Length: 1000\r\nLocation: /stored\r\n\r\ntruncated")
+		_ = buf.Flush()
+		_ = conn.Close()
+		close(closed)
+	}))
+	t.Cleanup(server.Close)
+
+	file, err := os.CreateTemp(t.TempDir(), "aggregate-*.parquet")
+	if err != nil {
+		t.Fatalf("CreateTemp: %s", err)
+	}
+	if _, err := file.WriteString("payload"); err != nil {
+		t.Fatalf("write temp aggregate: %s", err)
+	}
+	if err := file.Close(); err != nil {
+		t.Fatalf("close temp aggregate: %s", err)
+	}
+
+	_, signingKey, err := ed25519.GenerateKey(rand.Reader)
+	if err != nil {
+		t.Fatalf("GenerateKey: %s", err)
+	}
+	signingJWK, err := jwk.FromRaw(signingKey)
+	if err != nil {
+		t.Fatalf("FromRaw: %s", err)
+	}
+	if err := signingJWK.Set(jwk.AlgorithmKey, jwa.EdDSA); err != nil {
+		t.Fatalf("set Algorithm: %s", err)
+	}
+	if err := signingJWK.Set(jwk.KeyIDKey, "test-key"); err != nil {
+		t.Fatalf("set KeyID: %s", err)
+	}
+
+	aggrecURL, err := url.Parse(server.URL)
+	if err != nil {
+		t.Fatalf("parse server URL: %s", err)
+	}
+
+	edm := &dnstapMinimiser{
+		log:                 slog.New(slog.NewTextHandler(io.Discard, nil)),
+		httpClientCertStore: newCertStore(),
+	}
+	as, err := edm.newAggregateSender(aggrecURL, signingJWK, nil)
+	if err != nil {
+		t.Fatalf("newAggregateSender: %s", err)
+	}
+
+	start := time.Date(2026, 4, 29, 12, 34, 45, 0, time.UTC)
+	err = as.send(file.Name(), start, 45*time.Second)
+	if err == nil {
+		t.Fatal("expected error from send when response body is truncated")
+	}
+
+	select {
+	case <-closed:
+	case <-time.After(2 * time.Second):
+		t.Fatal("server handler did not run")
+	}
+}