With the Regent 's backing Nash created a master plan for the area , put into action from 1818 onwards , which stretched from St Jamesâ s northwards and included Regent Street , Regent 's Park and its neighbouring streets , terraces and crescents of elegant town houses and villas . With the Regent 's backing ( and major inputs from Repton ) , Nash created a master plan for the area , put into action from 1818 onwards , which stretched from St Jamesâ s northwards and included Regent Street , Regent 's Park and its neighbouring streets , terraces and crescents of elegant town houses and villas .