Not just towards St Paul's, but also to the Palace of Westminster. See the City of London's "Protected views and tall buildings" planning docs [1] and the section "Protected vistas in London" in the Wikipedia page Protected View [2].
Also, see the Wikipedia page on Greenwich Hospital, London [3]:
An early controversy arose when it emerged that the original plans for the hospital would have blocked the riverside view from the Queen's House. Queen Mary II therefore ordered that the buildings be split, providing an avenue leading from the river through the hospital grounds up to the Queen's House and Greenwich Hill beyond.
The resulting effect is displayed well in this contemporary pic:
