Law firm Trethowans has signed a 10-year lease on the Pavilion at Botleigh Grange Office Campus in Botley near Southampton.
The 23,560 sq ft building was spec built in 2008, a rarity for the area.
The Pavilion has remained vacant until recently. Consulting engineers White Young Green took a quarter of the offices earlier in the year. Trethowans will be occupying the remaining three-quarters of the building.
Hughes Ellard and CBRE jointly advised Helical Bar who bought the property two years ago in a joint venture with developer City Estates.
Trethowans was advised by Hughes Ellard.
Russell Mogridge, business space director at Hughes Ellard, said: “This is the largest office deal of its kind in recent memory, given that The Pavilion was a rare off-the-peg development, and it’s good to see this quality building finally buzzing with people.”