Vanbrugh's London Improvements

In the *London Journal* of March 16th, 1722-23, there is the following paragraph:— "We are informed that Sir John Vanbrugh, in his scheme for new paving the cities of London and Westminster, among other things, proposes a tax on all gentlemen's coaches, to stop all channels in the street, and to carry all the water off by drains and common sewers under ground." Sir John Vanbrugh was chiefly known as an architect of noblemen's and gentlemen's mansions. Can any of your readers supply me with a reference to any detailed plan, from Sir John, for the general improvement of the metropolis?