The deputy leader of the Ulster Unionist Party, Mr John Taylor, has described the resignation of Mr Peter Mandelson as untimely and damaging.
Mr Taylor also described Mr Mandelson's 'crimes' as minor, claiming there were irregularities in the issuing of passports in the Republic in the early 1990s.
"At this difficult time in the Northern Ireland political process the departure of Peter Mandelson is most untimely and damaging.
"We in Ulster know how hard Peter Mandelson worked to implement all aspects of the Belfast Agreement. Unionists did not agree with all his decisions but I personally want to place on record my appreciation of his efforts to bring lasting peace and political stability to Northern Ireland.