the a12 was formed in 1922 as part of the great britain road numbering scheme, and initially the route went from stratford to gallows corner along the present a118 road before continuing to great yarmouth. this section in london was rerouted to run on eastern avenue by the mid-1940s, and extended to follow the current route from blackwall tunnel along the east cross route, (previously the a102(m) & a106), the m11 link road in 1999.