Code: Select all
\documentclass[12pt,a4paper,fleqn,titlepage,twoside]{report}
\usepackage[T1]{fontenc}
\usepackage[latin1]{inputenc}
\usepackage[english]{babel}
%\usepackage{harvard}
\usepackage{blindtext}
\begin{document}
\bibliographystyle{dcu}
\pagenumbering{roman}
\tableofcontents \newpage
\listoffigures \newpage
\listoftables \newpage
\pagenumbering{arabic}
\begin{figure}[!ht]
\centering
\rule{12cm}{9cm}
\caption{\blindtext}\label{fig:testfigure}
\end{figure}
\end {document}
Regarding the fact that such long captions are unusual, you should think about setting a short caption in the optional argument of the \caption command.