Adding dot leaders in index

Question

How do I get the indexing (which I have set to 1 column) to use dot leaders? I have seen questions relating to tocloft, but this is for the TOC and not the index. Is there an idxlayout command I can use?

My index is of judgments and cases, which often have numbers as part of their citation, so instead of this:

The Prosecutor v Mitar Vasiljevic, Appeals Judgment IT-98-32-A, 1

I would prefer this:

The Prosecutor v Mitar Vasiljevic, Appeals Judgment IT-98-32-A.................1

(where the final "1" is the page number which has been indexed)

My MWE is:

\documentclass[bibliography=totoc,a4paper,openright]{scrbook}

\usepackage[backend=biber, style=oscola, indexing=cite]{biblatex}
\addbibresource{testingbiblio.bib} %necessary for Oscola
\usepackage[style=british]{csquotes} %necessary for Oscola

\usepackage[noautomatic,nonewpage]{imakeidx}
\makeindex[name=ICTY, columns=1, title={International Criminal Tribunal for Former 
Yugoslavia}]
\indexsetup{level=\chapter*} %no page break with chapters
\indexsetup{level=\section*} %no page break with sections

\newcommand{\startindices}{%
\chapter*{TABLE OF CASES}
\let\latexcleardoublepage\cleardoublepage
\def\cleardoublepage{%
\def\cleardoublepage{%
\global\let\cleardoublepage\latexcleardoublepage}}%
}

\begin{document}

Blah blah.\footcite{Vasiljevic}

\startindices
\chapter*{International Tribunals}
\printindex[ICTY]

\end{document}

My minimal bib database is:

@jurisdiction{Vasiljevic,
title = {The Prosecutor v Mitar Vasiljevi\'{c}, Appeals Judgment},
shorttitle = {Vasiljevi\'{c} Appeal},
date = {2004-02-25},
number = {IT-98-32-A},
court = {Appeals Chamber},
pagination = {paragraph},
tabulate = {ICTY},
keywords={ICTY}
}

Answer 1

You can do this at the MakeIndex style level.

Prepare a file intcases.ist with the following contents:

item_0 "\n \\noitem"
delim_0 "\\nobreak\\dotfill"

and then change your document into

\documentclass[bibliography=totoc,a4paper,openright]{scrbook}

\usepackage[backend=biber, style=oscola, indexing=cite]{biblatex}
\addbibresource{testingbiblio.bib} %necessary for Oscola
\usepackage[style=british]{csquotes} %necessary for Oscola

\usepackage{imakeidx}
\makeindex[
  name=ICTY,
  columns=1,
  options=-s intcases, % <---------- USE THE NEW MakeIndex STYLE
  title={International Criminal Tribunal for Former Yugoslavia},
]
\indexsetup{level=\chapter*} %no page break with chapters
\indexsetup{level=\section*} %no page break with sections

\newcommand{\startindices}{%
  \chapter*{TABLE OF CASES}
  \let\latexcleardoublepage\cleardoublepage
  \def\cleardoublepage{%
    \def\cleardoublepage{%
      \global\let\cleardoublepage\latexcleardoublepage
    }%
  }%
}

% the commands for typesetting the indices
\newcommand{\fillitem}{\nobreak\dotfill}
\newcommand{\noitem}{\par\noindent}

\begin{document}

Blah blah.\footcite{Vasiljevic}

\startindices
\chapter*{International Tribunals}
\printindex[ICTY]

\end{document}

If you really use the noautomatic option, you must remember to execute

makeindex -s intcases ICTY