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Steady state accretion discs larger than ~ 0.01-0.1 pc are known to begravitationally unstable for the accretion rates needed to explainsuper-massive black hole (SMBH) activity. We propose that SMBH are fed by asuccession of mass deposition events with randomly directed angular momenta.Because of incomplete angular momentum cancellation a warped accretion discforms in the inner few parsec. The orientation of the disc performs a randomwalk. Deposition of new material promotes SMBH accretion at rates much fasterthan viscous. Observational implications of this picture include: (i) lighteraccretion discs that can fuel AGN and quasars and yet avoid star formation at R>> 0.1 pc; (ii) star formation inside the disc is not a function of massaccretion rate only. It can take place at high or low accretion rates, e.g.,when too few clouds arrive in the inner region. An example of this might be thecentral parsec of our Galaxy. (iii) The discs can form Compton-thick obscuringstructures of ~ parsec size as required in AGN unification models; (iv) fasterblack hole growth resulting from misalignment of the disc and the black holespin in the early Universe; (v) Isotropic deposition of SMBH energy andmomentum feedback in the galaxy bulge. This may help explain the highefficiency with which it seems to be operating in the Universe. (vi) Nocorrelation between SMBH activity and the presence of kiloparsec scale bars orgaseous discs in galactic bulges; (vii) Bodily collisions between gaseouscomponents of merging galaxies facilitate production of gas streams feeding thecentre of the combined galaxy. Mergers should thus be catalysts of SMBH growth.(viii) Conversely, galaxies experiencing fewer mergers are more likely to formmassive nuclear star clusters than feed their SMBHs.

Forced accretion in stochastically fed AGN and quasars