The deal represents the first transaction of GRP after it became a unit of Brown & Brown.
With headquarters in Maidstone, England, First Insurance provides insurance products for the contracting industry including drainage, electrical, security and others.
Following the completion of the latest deal, First Insurance will become a part of GRP’s retail division.
The company is expected to continue to do business under its existing brand.
All employees of First Insurance including its chairman and founder Martin Bell, managing director Matthew Sendall-King and director Andrew Chibeba are set to operate from its current locations in Maidstone.
GRP group CEO Mike Bruce said: “The deal is our first since becoming part of the Brown & Brown family and underscores that it remains very much business as usual where our buy and build strategy for Retail is concerned.
“First Insurance is a quality regional broker and we look forward to working with Martin, Matthew and Andrew to build out their market presence.”
Bruce added: “We provide all our acquisitions with high value central support for HR, finance, compliance, operations and IT as well as funding and technical support to deliver their own growth plans.”
The deal enabled GRP to combine WTW’s £57m gross written premium (GWP) portfolio with its Northern Ireland brokerage, ABL Group.