diff --git a/src/components/settings/AccessibilitySettings.tsx b/src/components/settings/AccessibilitySettings.tsx
index 65fc629c..e62891ea 100644
--- a/src/components/settings/AccessibilitySettings.tsx
+++ b/src/components/settings/AccessibilitySettings.tsx
@@ -5,7 +5,7 @@ import Button from '../Button';
 import { spacing } from '../../theme/tokens';
 import { useLocaleStore } from '../../stores/locale-store';
 import { usePolicyStore, useSettingHidden, useSettingLocked } from '../../stores/policy-store';
-import { policyAllowsValue } from '../../lib/org-policy';
+import { isLockedSetting, policyAllowsValue } from '../../lib/org-policy';
 import { APP_FONTS, FONT_SIZES, useSettingsStore, type AppFont, type FontSize } from '../../stores/settings-store';
 import { uiFontsBundled } from '../../theme/reading-fonts';
 import { toast } from '../../stores/toast-store';
@@ -104,7 +104,15 @@ export function AccessibilitySettings() {
 
   const applyPreset = (id: AccessibilityPresetId) => {
     const name = presetName(id);
-    const changes = presetChanges(id, useSettingsStore.getState());
+    // Settings the organisation pins or bounds stay as they are (webmail
+    // accessibility-settings.tsx isSettingLocked, allowsValue).
+    const rules = usePolicyStore.getState().rules;
+    const changes = presetChanges(
+      id,
+      useSettingsStore.getState(),
+      (key) => isLockedSetting(rules, key),
+      (key, value) => policyAllowsValue(key, value, rules),
+    );
     if (changes.length === 0) {
       toast.info(t('settings.accessibility.presets.nothing_changed', '{name}: your settings already match.', { name }));
       return;
diff --git a/src/lib/__tests__/accessibility-presets-policy.test.ts b/src/lib/__tests__/accessibility-presets-policy.test.ts
new file mode 100644
index 00000000..37ff5e86
--- /dev/null
+++ b/src/lib/__tests__/accessibility-presets-policy.test.ts
@@ -0,0 +1,43 @@
+import { describe, it, expect } from 'vitest';
+import fs from 'node:fs';
+import path from 'node:path';
+import { presetChanges } from '../accessibility-presets';
+import { EMPTY_SETTINGS_RULES, isLockedSetting, policyAllowsValue, type SettingsRules } from '../org-policy';
+
+// Presets leave alone what the organisation pins or bounds (webmail
+// lib/accessibility-presets.ts presetChanges with isSettingLocked and
+// allowsValue). The app's presetChanges changed locked settings too.
+
+const read = (rel: string) => fs.readFileSync(path.resolve(__dirname, '..', '..', rel), 'utf8');
+
+describe('accessibility presets and the organisation policy', () => {
+  const state = { fontSize: 'medium' as const, showToolbarLabels: false };
+
+  it('skips a setting the organisation locked', () => {
+    expect(presetChanges('low-vision', state, (key) => key === 'fontSize'))
+      .toEqual([{ key: 'showToolbarLabels', from: false, to: true }]);
+  });
+
+  it('skips a value the organisation does not allow', () => {
+    const rules: SettingsRules = {
+      ...EMPTY_SETTINGS_RULES,
+      restrictions: { fontSize: { allowedValues: ['medium', 'large'] } },
+    };
+    const changes = presetChanges(
+      'low-vision',
+      state,
+      (key) => isLockedSetting(rules, key),
+      (key, value) => policyAllowsValue(key, value, rules),
+    );
+    expect(changes).toEqual([{ key: 'showToolbarLabels', from: false, to: true }]);
+  });
+
+  it('changes everything without a policy', () => {
+    expect(presetChanges('low-vision', state).map((c) => c.key)).toEqual(['fontSize', 'showToolbarLabels']);
+  });
+
+  it('passes the locks and bounds from Settings > Accessibility', () => {
+    const src = read('components/settings/AccessibilitySettings.tsx');
+    expect(src).toMatch(/presetChanges\(\s+id,\s+useSettingsStore\.getState\(\),\s+\(key\) => isLockedSetting\(rules, key\),\s+\(key, value\) => policyAllowsValue\(key, value, rules\),\s+\)/);
+  });
+});
diff --git a/src/lib/accessibility-presets.ts b/src/lib/accessibility-presets.ts
index 7303d020..79ae2cca 100644
--- a/src/lib/accessibility-presets.ts
+++ b/src/lib/accessibility-presets.ts
@@ -45,11 +45,20 @@ export interface PresetChange {
   to: unknown;
 }
 
-/** The changes a preset would make to `state`: only values that differ. */
-export function presetChanges(id: AccessibilityPresetId, state: Partial<PersistedSettings>): PresetChange[] {
+/**
+ * The changes a preset would make to `state`: only values that differ, and
+ * none the organisation has locked (`isLocked`) or bounded (`allows`, such
+ * as a minimum toast duration).
+ */
+export function presetChanges(
+  id: AccessibilityPresetId,
+  state: Partial<PersistedSettings>,
+  isLocked: (key: string) => boolean = () => false,
+  allows: (key: string, value: unknown) => boolean = () => true,
+): PresetChange[] {
   const changes: PresetChange[] = [];
   for (const [key, to] of Object.entries(ACCESSIBILITY_PRESETS[id]) as Array<[keyof PersistedSettings, unknown]>) {
-    if (!(key in state) || state[key] === to) continue;
+    if (!(key in state) || state[key] === to || isLocked(key) || !allows(key, to)) continue;
     changes.push({ key, from: state[key], to });
   }
   return changes;