The deal sees Deep Blue take over the 34 sites under the 90-year-old Harry Ramsden’s brand, debt free, including its restaurants in Ireland and Malaysia.
BRG will retain an interest in the enlarged business.
Deep Blue, which already runs 26 sites in the south and east of England, says the deal sees it become the largest player in the fish and chip market “by a considerable margin”.
It intends to keep the Harry Ramden's branding and build on its "strength both nationally and internationally".
“Our amalgamation with Harry Ramsden’s is a key milestone in our development but we remain committed to exploiting the unparalleled opportunities within the sector for further expansion,” says James Low, founder and CEO of Deep Blue.
BRG says the deal will “simplify” its business and allow it to focus on its core Giraffe, Ed’s Easy Diner and Fishworks brands.
Twenty-seven Giraffe and Ed’s restaurants closed earlier this year under a Company Voluntary Arrangement (CVA).
BRG is continuing to roll out US import Slim Chickens, which it runs under franchise.