diff --git a/portal/migrations/versions/4f5daa2b48db_.py b/portal/migrations/versions/4f5daa2b48db_.py
new file mode 100644
index 000000000..31246e664
--- /dev/null
+++ b/portal/migrations/versions/4f5daa2b48db_.py
@@ -0,0 +1,24 @@
+"""remove non english rows from report data (IRONN-264)
+
+Revision ID: 4f5daa2b48db
+Revises: 967a074a0404
+Create Date: 2024-11-25 13:48:01.321510
+
+"""
+from alembic import op
+
+
+# revision identifiers, used by Alembic.
+revision = '4f5daa2b48db'
+down_revision = '967a074a0404'
+
+
+def upgrade():
+    connection = op.get_bind()
+    connection.execute("DELETE FROM research_data WHERE NOT (data->>'timepoint' ~ '^(Baseline|Month)');")
+    # next run of `cache_research_data()` will pick up those just deleted.
+
+
+def downgrade():
+    # no point in bringing those back
+    pass