Memoirs of the Life and Administration of Sir Robert Walpole

The source of Walpole's denial, delivered in the Commons on 13 February 1741 on Samuel Sandys' motion for an address seeking his removal. As Coxe gives it:

But while I unequivocally deny that I am sole and prime-minister, and that to my influence and direction all the measures of government must be attributed, yet I will not shrink from the responsibility which attaches to the post I have the honour to hold...

One caveat the essay does not need but the record should carry. Coxe's footnote says the substance is taken from parliamentary minutes in Walpole's own handwriting, together with Chandler's Debates. Hansard did not exist until 1803 and verbatim reporting of Parliament was then prohibited, so eighteenth-century speeches were written up afterwards. The wording is attested in a documented 1798 source drawing on Walpole's own notes; it is not a transcript.