A&O: took Norton Rose team within 12-month notice periodAllen & Overy (A&O) is engaged in what appears to be a losing battle with top Wall Street firm Simpson Thacher & Bartlett over restrictive covenants the magic circle firm has imposed on departing acquisition finance partner Euan Gorrie.

Sources close to Simpson Thacher claim A&O has so far refused to lift tough client restrictions imposed on Gorrie after his resignation on 30 October, with top client JP Morgan Chase emerging as a particular cause of concern for the UK firm.