beamerouterthemeWarwick.sty

\mode<presentation>
\setbeamersize{text margin left=1cm,text margin right=1cm}

\newcommand{\warwicklogo}[1]{
  \begin{minipage}[t]{#1}

\resizebox{#1}{!}{
\begin{tikzpicture}
    \fill[wwmaincolour]
            (0.03,0.99cm) -- 
            (1.49cm,0.99cm) -- 
            (1.49cm,0.03) -- 
            (0.03,0.03) --
            cycle;

      \node[anchor=south west,inner sep=0pt] (logoleft) at (0,0)[]{
          \includegraphics[width=1.5cm]{logo-with-descriptor-square}};
  \end{tikzpicture}
}
\end{minipage}
}

\newcommand{\gettikzxy}[3]{%
  \tikz@scan@one@point\pgfutil@firstofone#1\relax
  \edef#2{\the\pgf@x}%
  \edef#3{\the\pgf@y}%
}

  
% Frame title
\defbeamertemplate*{frametitle}{Warwick}[1][]
{
%\vskip0.5cm%
  \begin{beamercolorbox}[wd=\paperwidth,ht=1.5cm]{frametitle} 
  \begin{tikzpicture}
  \useasboundingbox[fill=white](0,-0.5) rectangle(\the\paperwidth,\the\paperheight);
   \node (A) at (\the\paperwidth,\the\paperheight){};
  \gettikzxy{(A)}{\ax}{\ay}

      \if@doWarwickMain{
        \if@doExternal{
           \fill [wwsurroundcolour]
              (0,\the\paperheight) -- 
              (\the\paperwidth,\the\paperheight) -- 
              (\the\paperwidth,0.7cm-0.099\paperwidth) -- 
              (0,0.7cm-0.099\paperwidth) --
              cycle;}
        \else{
           \fill [wwsurroundcolour]
               (0,\the\paperheight) -- 
              (\the\paperwidth,\the\paperheight) -- 
              (\the\paperwidth,0.7cm-0.075\paperwidth) -- 
              (0,0.7cm-0.075\paperwidth) --
              cycle;}
        \fi
      }
      \else{
        \fill [wwsurroundcolour]
               (0,\the\paperheight) -- 
              (\the\paperwidth,\the\paperheight) -- 
              (\the\paperwidth,0.7cm-0\paperwidth) -- 
              (0,0.7cm-0\paperwidth) --
              cycle;
      }
      \fi

      \node[anchor=north west,inner sep=0pt] (logoleft) at (-0.01,0.7)[]{
          \includegraphics[width=1.001\paperwidth]{logo-with-descriptor}};

        % \node[fill] (A) at (\ax-2.5cm+1.3cm,0){};
   
   \ifx\insertframesubtitle\@empty%
      {\node[anchor=west, font=\Large] at (15pt,0){\insertframetitle};}
      \else%
      {\node[anchor= west, font=\large] at (15pt,0.2){\insertframetitle};%
       \node[anchor= west, font=\small] at (1.5,-0.2){\insertframesubtitle};}%
      \fi
  \end{tikzpicture}
  \end{beamercolorbox}
%\vskip0.3cm%
}

\setbeamertemplate{background}{
  \begin{tikzpicture}
  \useasboundingbox (0,0) rectangle(\the\paperwidth,\the\paperheight);
  \ifnum\thepage>1\relax%
\ifbeamercolorempty[bg]{background canvas}{}{\color{bg}}%
   \fill[wwsurroundcolour!0] (0,0) rectangle(\the\paperwidth,\the\paperheight);
   \fi
  \end{tikzpicture}
}

\setbeamertemplate{footline}
{
  \leavevmode%
  \hbox{%
  \begin{beamercolorbox}[wd=.5\paperwidth,ht=2.25ex,dp=1ex,center]{author in head/foot}%
    \usebeamerfont{author in head/foot}\insertshortauthor~~\beamer@ifempty{\insertshortinstitute}{}{(\insertshortinstitute)}
  \end{beamercolorbox}%
  \begin{beamercolorbox}[wd=.5\paperwidth,ht=2.25ex,dp=1ex,right]{date in head/foot}%
    \usebeamerfont{date in head/foot}\insertshortdate{}\hspace*{2em}
    \insertframenumber{} / \inserttotalframenumber\hspace*{2ex} 
  \end{beamercolorbox}}%
  \vskip0pt%
}

% % Title page
\defbeamertemplate*{title page}{Warwick}[1][]
{ 

  \begin{beamercolorbox}[wd=\paperwidth,ht=1.8cm]{frametitle} 
  \begin{tikzpicture}
  \useasboundingbox[fill=white](0,-1) rectangle(\the\paperwidth,\the\paperheight);
  \node (A) at (\the\paperwidth,\the\paperheight){};
  \gettikzxy{(A)}{\ax}{\ay}

  \if@doWarwickFront{
      
      \if@doExternalFront{
         \fill [wwsurroundcolour]
            (0,\the\paperheight) -- 
            (\the\paperwidth,\the\paperheight) -- 
            (\the\paperwidth,0.7cm-0.099\paperwidth) -- 
            (0,0.7cm-0.099\paperwidth) --
            cycle;}
      \else{
         \fill [wwsurroundcolour]
             (0,\the\paperheight) -- 
            (\the\paperwidth,\the\paperheight) -- 
            (\the\paperwidth,0.7cm-0.075\paperwidth) -- 
            (0,0.7cm-0.075\paperwidth) --
            cycle;}
      \fi
    }
    \else{
        \fill [wwsurroundcolour]
               (0,\the\paperheight) -- 
              (\the\paperwidth,\the\paperheight) -- 
              (\the\paperwidth,0.7cm-0\paperwidth) -- 
              (0,0.7cm-0\paperwidth) --
              cycle;
    }
    \fi


      \node[anchor=north west,inner sep=0pt] (logoleft) at (-0.01,0.7)[]{
          \includegraphics[width=1.001\paperwidth]{logo-with-descriptor}};
    
  \end{tikzpicture}
  \end{beamercolorbox}
%%%%%%%%%%%%%%%%%%%%%
    \begin{beamercolorbox}[sep=8pt,center,#1]{title}
      \usebeamerfont{title}\inserttitle\par%
    \end{beamercolorbox}%
    % \vskip0.05cm%
    \begin{beamercolorbox}[sep=8pt,center,#1]{author}
      \usebeamerfont{author}\insertauthor%
    \end{beamercolorbox}
     % \vskip0.05cm%
    \begin{beamercolorbox}[center,#1]{date}
      \usebeamerfont{author}\insertdate%
    \end{beamercolorbox}
  \vfill
}
\mode<all>