Exclusive J/$\psi$ photoproduction cross section off protons measured as a function of the centre-of-mass energy of the photon--proton system $W_{\gamma {\rm p}}$ by ALICE in p$-$Pb UPCs and compared with previous measurements and with next-to-leading-order JMRT and CCT models. The power-law fit to the ALICE data is also shown. The uncertainties of the data points are the quadratic sum of the statistical and systematic uncertainties.