The chair of the in-house lobbying group GC100 has called on law firms to ensure that all potential partners spend at least two spells on secondment at companies.

Helen Mahy, general counsel and company secretary of FTSE100 company National Grid, told The Lawyer: “I can’t see that secondments give anything other than an advantage to private practice lawyers. Clearly, they get to see what it’s like to work as a client.”

Mahy, who heads a team of around 100 in-house lawyers across the UK and the US, has long been enthusiastic about secondments across practice areas, not just from panel firms CMS Cameron McKenna and Linklaters, but also from firms such as Eversheds.

She has pushed for arrangements such as reverse secondments, in which her trainees have gone to firms for one seat. “Reverse secondments are rarer and much more difficult to organise, but they’re very good for in-house lawyers,” she said.

Mahy has also pioneered a six-month job swap with the legal function of Alliance & Leicester and is currently reviewing whether to organise a second.

“Although firms are generally open to secondments, the M&A boom has meant that secondees have been rarer and more expensive,” she added.