Macfarlanes and Herbert Smith have lined up to advise on the acquisition of marketing company Tag by business process outsourcer Williams Lea.

Macfarlanes advised Williams Lea led by corporate partner Stephen Drewitt, while Herbert Smith advised Tag, led by corporate partner James MacArthur. Drewitt previously advised private equity group 3i on the £110m sale of its 38% stake in Williams Lea to Deutsche Post in 2006.

Tag posted revenues of £100m last year. It will continue to operate under its own brand as a standalone business division of Williams Lea and subsidiary of Deutsche Post. The deal value has not been disclosed.

Drewitt commented: "I was introduced to the management team at Williams Lea in 2004 when acting for 3i on its investment in Williams Lea. It has been very rewarding to work alongside them since then: most obviously on the sale by 3i to Deutsche Post in 2006 and now on this important strategic transaction.

"The transaction follows a trend that we are seeing – which is our successful international corporate clients having renewed confidence to make investment decisions decisively when the right opportunities arise."

Tag, which employs more than 1,000 staff, is the world's largest independent marketing execution and production agency advising clients on branding and advertising campaigns.

Beachcroft announced last May that it was to outsource a number of its back-office functions, including data support, reception, post, copying and filing, to Williams Lea.

The Tag mandate comes in the same month that Herbert Smith secured a lead role advising Ernst & Young as administrator of Nortel Network's entities in Europe, the Middle East and Africa on the sale of a portfolio of patents to a consortium of IT companies.