The Hanover Insurance Group, Inc. (THG) S-8 Registration of securities for employees

Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We hereby consent to the incorporation by reference in this Registration Statement on Form S-8 of our report dated March 16, 2006 relating to the financial statements, financial statement schedules, management’s assessment of the effectiveness of internal control over financial reporting and the effectiveness of internal control over financial reporting, of The Hanover Insurance Group, Inc., which appears in The Hanover Insurance Group, Inc.’s Annual Report on Form 10-K for the year ended December 31, 2005.

PricewaterhouseCoopers LLP

Boston, Massachusetts

May 17, 2006