EXHIBIT 23.1 ARTHUR ANDERSEN LLP CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS As independent public accountants, we hereby consent to the incorporation by reference in this registration statement on Form S-8 of our report dated January 29, 1996, included in the Annual Report on Form 10-K of UST Corp. for the year ended December 31, 1995, and to all references to our Firm included in this registration statement. /s/ Arthur Andersen LLP ARTHUR ANDERSEN LLP Boston, Massachusetts June 13, 1996