diff --git a/package.json b/package.json
index 4b6112a..faa35f1 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "processout.js",
-  "version": "1.9.10",
+  "version": "1.9.11",
   "description": "ProcessOut.js is a JavaScript library for ProcessOut's payment processing API.",
   "scripts": {
     "build:processout": "tsc -p src/processout && uglifyjs --compress --keep-fnames --ie8 dist/processout.js -o dist/processout.js",
diff --git a/src/apm/elements/phone.ts b/src/apm/elements/phone.ts
index 996cbf8..1bc0012 100644
--- a/src/apm/elements/phone.ts
+++ b/src/apm/elements/phone.ts
@@ -243,6 +243,15 @@ module ProcessOut {
 
       if (currentValue.length < getDialingCode(dialingCode).length) {
         phoneNumber = cleanNumber;
+        // Propagate the (now empty/cleared) number to the form so validation
+        // reflects it — otherwise clearing the field back into the dialing-code
+        // prefix leaves a stale value in the form and required checks pass.
+        if (state.number !== phoneNumber) {
+          oninput && oninput(name, {
+            dialing_code: dialingCode,
+            number: phoneNumber,
+          });
+        }
         dialingCodesRef.focus()
         dialingCodesRef.showPicker()
         setState({
diff --git a/src/apm/utils.ts b/src/apm/utils.ts
index 55fd75b..e557b1d 100644
--- a/src/apm/utils.ts
+++ b/src/apm/utils.ts
@@ -81,6 +81,29 @@ module ProcessOut {
     return proto === null || proto === Object.prototype;
   }
 
+  /**
+   * Normalise a form field value to the scalar used for validation.
+   *
+   * Most fields are primitives, but the phone field is an object. The Phone
+   * component emits the number under `number` once the shopper interacts, while
+   * the initial/prefilled seed carries it under the legacy `value` key. We read
+   * whichever is present (`number` first, as it is the canonical key), otherwise
+   * validation (e.g. the required check) sees a non-empty object and silently
+   * passes even when the number has been cleared.
+   */
+  export function getComparableFieldValue(value: unknown): unknown {
+    if (isPlainObject(value)) {
+      const record = value as Record<string, unknown>;
+      if ('number' in record) {
+        return record.number;
+      }
+      if ('value' in record) {
+        return record.value;
+      }
+    }
+    return value;
+  }
+
   export const isEmpty = (value: Record<string, unknown> | Array<any>): boolean => {
     if (Array.isArray(value)) {
       return value.length === 0;
diff --git a/src/apm/views/utils/form.ts b/src/apm/views/utils/form.ts
index ad2ddb3..26c4e34 100644
--- a/src/apm/views/utils/form.ts
+++ b/src/apm/views/utils/form.ts
@@ -24,12 +24,7 @@ module ProcessOut {
       return
     }
 
-    let actualValue;
-    if (isPlainObject(value) && 'value' in value) {
-      actualValue = value.value;
-    } else {
-      actualValue = value;
-    }
+    const actualValue = getComparableFieldValue(value);
 
     switch (true) {
       case validation.required &&
diff --git a/test/apm/phone-validation.test.ts b/test/apm/phone-validation.test.ts
new file mode 100644
index 0000000..1b2ac65
--- /dev/null
+++ b/test/apm/phone-validation.test.ts
@@ -0,0 +1,79 @@
+import { describe, expect, it } from "vitest"
+import { loadApmUtils } from "../support/loadNamespace"
+
+const { getComparableFieldValue } = loadApmUtils()
+
+/**
+ * Regression coverage for the phone "required" validation bug: the Phone
+ * component emits its value under `number`, while the initial/prefilled seed
+ * uses the legacy `value` key. The validator normalises both via
+ * getComparableFieldValue, so an empty phone number is recognised as empty
+ * regardless of which shape is present (previously the `number` shape was
+ * treated as a non-empty object and the required check silently passed).
+ */
+describe("getComparableFieldValue", () => {
+  it("returns primitives unchanged", () => {
+    expect(getComparableFieldValue("hello")).toBe("hello")
+    expect(getComparableFieldValue("")).toBe("")
+    expect(getComparableFieldValue(0)).toBe(0)
+    expect(getComparableFieldValue(undefined)).toBe(undefined)
+  })
+
+  it("reads the number from the emitted `number` shape", () => {
+    expect(
+      getComparableFieldValue({ dialing_code: "+44", number: "7911123456" }),
+    ).toBe("7911123456")
+  })
+
+  it("reads the number from the legacy seed/prefill `value` shape", () => {
+    expect(
+      getComparableFieldValue({ dialing_code: "+44", value: "7911123456" }),
+    ).toBe("7911123456")
+    expect(getComparableFieldValue({ dialing_code: "+44", value: "" })).toBe("")
+  })
+
+  it("returns an empty string for a cleared `number` (the reported bug)", () => {
+    // Shopper typed a number then removed it: the value is now { number: "" }.
+    // This must resolve to "" so the required check fires.
+    expect(getComparableFieldValue({ dialing_code: "+44", number: "" })).toBe("")
+  })
+
+  it("prefers the canonical `number` when both keys are present", () => {
+    expect(
+      getComparableFieldValue({ value: "from-value", number: "from-number" }),
+    ).toBe("from-number")
+  })
+
+  it("returns the object unchanged when neither key is present", () => {
+    const obj = { dialing_code: "+44" }
+    expect(getComparableFieldValue(obj)).toBe(obj)
+  })
+})
+
+/**
+ * Mirrors form.ts validateField's required rule against the normalised value,
+ * documenting the end-to-end expectation the SDK relies on.
+ */
+function isMissingRequired(value: unknown): boolean {
+  const actualValue = getComparableFieldValue(value)
+  return (
+    typeof value === "undefined" ||
+    (typeof actualValue === "string" && actualValue.length === 0)
+  )
+}
+
+describe("required check on phone values", () => {
+  it("flags an empty phone number in either shape", () => {
+    expect(isMissingRequired({ dialing_code: "+44", value: "" })).toBe(true)
+    expect(isMissingRequired({ dialing_code: "+44", number: "" })).toBe(true)
+  })
+
+  it("accepts a provided phone number in either shape", () => {
+    expect(isMissingRequired({ dialing_code: "+44", value: "7911123456" })).toBe(
+      false,
+    )
+    expect(
+      isMissingRequired({ dialing_code: "+44", number: "7911123456" }),
+    ).toBe(false)
+  })
+})