Together Grissell and Peto built up a rapidly growing business, controlling all their operations from stone-quarrying to the manufacture of fittings for their buildings. Grissell claimed to have made innovations in building technique, including a form of braced and bolted timber scaffolding. They were awarded the contract for Birmingham Grammar School (with Charles Barry as architect). They next constructed a number of prestigious buildings in London, including Hungerford Market in the Strand; Nelson's Column; the Reform Club, Conservative Club, Oxford and Cambridge Club, Clerkenwell Prison, the Lyceum Theatre and St. James' Theatre.