Law firm merger activity picked up after a sluggish first quarter in part due to a renewed increase in transatlantic marriages between large domestic firms and those headquartered in England.

Among the 10 mergers reported last quarter by legal consultancy Hildebrandt Baker Robbins -- one more than during that time frame last year -- was the union of Washington stalwart Hogan & Hartson and London-based Lovells to form Hogan Lovells, which the report characterized as the second-largest since Hildebrandt began tracking quarterly merger activity.

A second cross-border marriage of equals, between Chicago-based Sonnenschein Nath & Rosenthal and London's Denton Wilde Sapte, was announced last quarter but is not included in that figure because the merger will not be completed until later in the year.

Industry analysts say that after a period of caution, U.S. firms are once again looking for markets in which to expand -- and the obvious one for some is London, where many firms specialize in the kind of corporate transaction work that has long been the bread and butter of New York.