In Britain, it is not uncommon for a junior lawyer from a legal department to spend some time with a law firm, especially to gain litigation experience. An example comes from Law Bus. Rev., Winter 2009 at 30, which cites MITIE doing such a reverse secondment with Burges Salmon (See my post of Oct. 26, 2005: reverse secondment of paralegals; June 13, 2006: bilateral secondments; and Aug. 18, 2008: BT honors two-way secondments.). A trainee lawyer from the department took part in the arrangement.
The permeable interchange of lawyers illustrates another form of partnership as well as intervention (See my post of July 17, 2008: secondment with 12 references; Jan. 23, 2008: secondments with 8 references; and Aug. 11, 2009: secondment arrangements with 10 references.).