Nabarro has scooped the top prize for its vacation scheme in the National Council for Work Experience (NCWE) 2012 awards.
Meanwhile, Simmons & Simmons was highly commended for its work placement.
Nabarro trainee resources manager Jane Drew said: “The programme has been carefully designed to ensure all participants get the maximum benefit from their time with us and the opportunity to showcase their initiative, passion for law, technical competence and ability to perform under pressure.
“It’s so effective that we take over 90 per cent of trainees from the graduate scheme each year.”
The NCWE awards recognise a variety of organisations that provide exceptional students and graduate internships.