diff --git uc_vat.admin.inc uc_vat.admin.inc
index c1d0aa5..216aa84 100644
--- uc_vat.admin.inc
+++ uc_vat.admin.inc
@@ -39,24 +39,40 @@ function uc_vat_settings_form($form_state) {
   $form['edit'] = array(
     '#type' => 'fieldset',
     '#title' => t('Price editing options'),
+    '#collapsible' => TRUE,
+  );
+  $form['edit']['prices'] = array(
+    '#type' => 'fieldset',
+    '#title' => t('Prices'),
     '#description' => t('Select the price fields below that you will enter inclusive of !tax.', array('!tax' => $tax)),
     '#collapsible' => TRUE,
   );
-  $form['edit']['uc_vat_list_price_inclusive'] = array(
+  $form['edit']['prices']['uc_vat_list_price_inclusive'] = array(
     '#type' => 'checkbox',
     '#title' => t('List price'),
     '#default_value' => variable_get('uc_vat_list_price_inclusive', FALSE),
   );
-  $form['edit']['uc_vat_cost_inclusive'] = array(
+  $form['edit']['prices']['uc_vat_cost_inclusive'] = array(
     '#type' => 'checkbox',
     '#title' => t('Cost'),
     '#default_value' => variable_get('uc_vat_cost_inclusive', FALSE),
   );
-  $form['edit']['uc_vat_sell_price_inclusive'] = array(
+  $form['edit']['prices']['uc_vat_sell_price_inclusive'] = array(
     '#type' => 'checkbox',
     '#title' => t('Sell price'),
     '#default_value' => variable_get('uc_vat_sell_price_inclusive', FALSE),
   );
+  $form['edit']['attributes'] = array(
+    '#type' => 'fieldset',
+    '#title' => t('Attributes'),
+    '#collapsible' => TRUE,
+  );
+  $form['edit']['attributes']['uc_vat_default_attributes_inclusive'] = array(
+    '#type' => 'checkbox',
+    '#title' => t('Enter default attributes inclusive of !tax.', array('!tax' => $tax)),
+    '#description' => t('Only applicable if Cost and or Sell price are enabled as !tax inclusive above. This should only be enabled in stores where all products will be taxed at a single tax rate.', array('!tax' => $tax)),
+    '#default_value' => variable_get('uc_vat_default_attributes_inclusive', FALSE),
+  );
 
   $form['checkout'] = array(
     '#type' => 'fieldset',
diff --git uc_vat.install uc_vat.install
index 65087c0..9463ede 100644
--- uc_vat.install
+++ uc_vat.install
@@ -2,6 +2,13 @@
 // $Id: uc_vat.install,v 1.1 2009/10/05 15:34:08 longwave Exp $
 
 /**
+ * Implementation of hook_uninstall().
+ */
+function uc_vat_uninstall() {
+  db_query("DELETE FROM {variable} WHERE name LIKE 'uc_vat_%%'");
+}
+
+/**
  * Split "enter prices inclusive of VAT" option.
  */
 function uc_vat_update_6000() {
diff --git uc_vat.module uc_vat.module
index 5ffb594..83e65b6 100644
--- uc_vat.module
+++ uc_vat.module
@@ -230,18 +230,104 @@ function _uc_vat_uc_order_edit_products_submit() {
   }
 }
 
+/**
+ * Alter default attribute options overview form to add VAT if necessary.
+ */
 function uc_vat_form_uc_attribute_options_form_alter(&$form, $form_state) {
-  if (_uc_vat_attribute_fields()) {
+  if ($fields = _uc_vat_attribute_fields()) {
+    if (variable_get('uc_vat_default_attributes_inclusive', FALSE)) {
+      $attribute = uc_attribute_load($form['aid']['#value']);
+      $context = array(
+        'revision' => 'themed',
+        'type' => 'attribute_option',
+        'subject' => array(
+          'attribute' => $attribute,
+        ),
+      );
+      $taxes = uc_taxes_rate_load();
+
+      foreach ($attribute->options as $oid => $option) {
+        foreach ($fields as $field) {
+          $value = $option->$field;
+          // Apply all taxes as this is a default attribute and product type is
+          // not yet known.
+          foreach ($taxes as $tax) {
+            $value *= (1 + $tax->rate);
+          }
+          $context['subject']['option'] = $option;
+          $context['field'] = $field;
+          $form['options'][$oid][$field]['#value'] = uc_price($value, $context);
+        }
+      }
+
+      $name = variable_get('uc_vat_name', 'VAT');
+      $message = variable_get('uc_vat_cost_inclusive', FALSE) ? t('"Default cost" column includes !tax.', array('!tax' => $name)) : t('"Default cost" column excludes !tax.', array('!tax' => $name));
+      $message .= ' ';
+      $message .= variable_get('uc_vat_sell_price_inclusive', FALSE) ? t('"Default price" column includes !tax.', array('!tax' => $name)) : t('"Default price" column excludes !tax.', array('!tax' => $name));
+    }
+
+    else {
+      $message = t('Prices shown here are exclusive of !tax. !tax will be added where applicable when these attributes are added to products.', array('!tax' => variable_get('uc_vat_name', 'VAT')));
+    }
+
     $form['vat_note'] = array(
       '#type' => 'markup',
-      '#value' => '<p>'. t('Prices shown here are exclusive of !tax. !tax will be added where applicable when these attributes are added to products.', array('!tax' => variable_get('uc_vat_name', 'VAT'))) .'</p>',
+      '#value' => '<p>'. $message .'</p>',
     );
   }
 }
 
+/**
+ * Alter default attribute options edit form to add VAT if necessary.
+ */
 function uc_vat_form_uc_attribute_option_form_alter(&$form, $form_state) {
-  if (_uc_vat_attribute_fields()) {
-    $form['adjustments']['#description'] .= '<br />'. t('Prices entered must exclude !tax. !tax will be added where applicable when this attribute is added to a product.', array('!tax' => variable_get('uc_vat_name', 'VAT')));
+  if ($fields = _uc_vat_attribute_fields()) {
+    if (variable_get('uc_vat_default_attributes_inclusive', FALSE)) {
+      $attribute = uc_attribute_load($form['aid']['#value']);
+      $option = $attribute->options[$form['oid']['#value']];
+      $taxes = uc_taxes_rate_load();
+
+      foreach ($fields as $field) {
+        $value = $option->$field;
+        // Apply all taxes as this is a default attribute and product type is
+        // not yet known.
+        foreach ($taxes as $tax) {
+          $value *= (1 + $tax->rate);
+        }
+        $form['adjustments'][$field]['#default_value'] = uc_store_format_price_field_value(round($value, 4));
+      }
+
+      // Ensure our submit handler gets called first to remove VAT from the
+      // price entered.
+      array_unshift($form['#submit'], 'uc_vat_uc_attribute_option_form_submit');
+
+      $name = variable_get('uc_vat_name', 'VAT');
+      $message = variable_get('uc_vat_cost_inclusive', FALSE) ? t('"Cost" includes !tax.', array('!tax' => $name)) : t('"Cost" excludes !tax.', array('!tax' => $name));
+      $message .= ' ';
+      $message .= variable_get('uc_vat_sell_price_inclusive', FALSE) ? t('"Price" includes !tax.', array('!tax' => $name)) : t('"Price" excludes !tax.', array('!tax' => $name));
+    }
+    else {
+      $message = t('Prices entered must exclude !tax. !tax will be added where applicable when this attribute is added to a product.', array('!tax' => variable_get('uc_vat_name', 'VAT')));
+    }
+
+    $form['adjustments']['#description'] .= '<br />'. $message;
+  }
+}
+
+/**
+ * Remove VAT from default option prices.
+ */
+function uc_vat_uc_attribute_option_form_submit($form, &$form_state) {
+  $taxes = uc_taxes_rate_load();
+
+  foreach (_uc_vat_attribute_fields() as $field) {
+    $value = $form_state['values'][$field];
+    // Apply all taxes as this is a default attribute and product type is not
+    // yet known.
+    foreach (array_reverse($taxes) as $tax) {
+      $value /= (1 + $tax->rate);
+    }
+    $form_state['values'][$field] = $value;
   }
 }