Exhibit 23.1 CONSENT OF INDEPENDENT ACCOUNTANTS As independent accountants, we consent to the incorporation by reference in this Current Report on Form 8-K/A, of our report dated January 29, 1996 included in UST Corp.'s Form 10-K for the year ended December 31, 1995 and to all references to our Firm included in this Current Report. /s/ Arthur Andersen LLP Arthur Andersen LLP Boston, Massachusetts February 28, 1997