  We fit the available data on exclusive semileptonic $b\to u\ell^-\bar\nu$
decays within the Standard Model and in the Weak Effective Theory. Assuming
Standard Model dynamics, we find $|V_{ub}| = 3.59^{+0.13}_{-0.12} \times
10^{-3}$. Lifting this assumption, we obtain stringent constraints on the
coefficients of the $ub\ell\nu$ sector of the Weak Effective Theory. Performing
a Bayesian model comparison, we find that a beyond the Standard Model
interpretation is favoured over a Standard Model interpretation of the
available data. We provide a Gaussian mixture model that enables the efficient
use of our fit results in subsequent analyses beyond the Standard Model, within
and beyond the framework of the Standard Model Effective Field Theory.
