The six-month term is fixed by Herbert Smith’s partnership deed. However, other high-profile departees were not held to it, including Robert Volterra, who went to Latham & Watkins earlier this year, and Gerald Bland, who joined Wragge & Co in 2002.
A Herbert Smith spokesperson said: “After 20 years Stephen has decided to leave with a view to considering other options.” He added that the firm’s competition department had had its best year to date.
Kinsella was unavailable for comment.