How to avoid widow lines in Table of contents (TOC)

Question

I have a Table of Contents page (the last page, page 3) which just has one line on it. Is there a way of manually editing it so, say, Chapter 3 starts on page 2, as opposed to straddling pages 1 and 2? This would presumably push the rest of everything down and lead to a more "balanced" page 3.

Here are some relevant [I hope!] files:

\let\oldtableofcontents = \tableofcontents
\renewcommand{\tableofcontents}{ 
\newpage
\pagestyle{plain}
\begin{singlespace} 
\oldtableofcontents 
\end{singlespace}}

Answer 1

There are a number of options, but in answer to your question, you can insert a page break in the ToC at any point within the document flow by using:

\addtocontents{toc}{\protect\newpage}

You would add the above just before \chapter{<chapter 3>} (see also How can I force ToC not to end with a chapter?). An alternative would be to insert a \enlargethispage{\baselineskip} in the ToC

\addtocontents{toc}{\protect\enlargethispage{\baselineskip}}

at the appropriate location (see also Change margins on the first of \tableofcontents page only). However, this may not be suitable as it would yield an uneven page block in the ToC.