Firefly beat Hotwire PR, Octopus, Nelson Bostock Communications and Companycare to the account.
The incumbent, Pleon, held the account for about three years.
Firefly has been hired to ‘get the TMC name known more widely’ through national, vertical and broadcast media, according to Firefly head of corporate Jon Holt.
He said the campaign would aim to ensure that the TMC practice was considered the ‘default specialist’ in telecoms, media and commercial law.
TMC represents more than 200 lawyers with specialisms ranging from intellectual property, data protection, software rights and digital media to broadcast and sport. The practice is seeking to expand into other areas, such as gambling.