William Morris was one of the founders of SPAB, the Society for the Preservation of Ancient Buildings, in 1877, more details here. It was established in response to the work of Victorian architects whose enthusiasm for harmful restoration caused irreparable damage. These two houses, 41-43 Great Ormond Street with the blue doors, were the SPAB’s first premises. The rooms on the first floor were knocked through, which was useful for lectures and committee meetings. Motto for today: ‘We are only trustees for those that come after us’ William Morris.