  Correlation functions of the composite field $T\bar{T}$ in the scaling
Lee--Yang model are studied. Using the analytic expression for form factors of
this operator recently proposed by Delfino and Niccoli \cite{DN}, we show
numerically that the constraints on the $T\bar{T}$ expectation values obtained
in \cite{AZ_VEVTT} and the additional requirement of asymptotic behavior lead
to a perfect agreement with the ultraviolet asymptotic predicted by the
conformal perturbation theory.
