--- /dev/null
+<?php
+
+namespace Drupal\comment\Plugin\views\field;
+
+use Drupal\views\Plugin\views\field\EntityField;
+use Drupal\views\ResultRow;
+
+/**
+ * Field handler to display the depth of a comment.
+ *
+ * @ingroup views_field_handlers
+ *
+ * @ViewsField("comment_depth")
+ */
+class Depth extends EntityField {
+
+ /**
+ * {@inheritdoc}
+ */
+ public function getItems(ResultRow $values) {
+ $items = parent::getItems($values);
+
+ foreach ($items as &$item) {
+ // Work out the depth of this comment.
+ $comment_thread = $item['rendered']['#markup'];
+ $item['rendered']['#markup'] = count(explode('.', $comment_thread)) - 1;
+ }
+ return $items;
+ }
+
+}