By Guy Taylor Shipbroker Clarkson is facing a shareholder revolt over the hefty pay packet of its chief executive Andi Case. The FTSE 250 firm handed the shipping executive £11.9m last year, up from £10.4m, after arecord financial performance. Case, who has led the firm since 2008, is one of the most highly paid senior executives in London. According to The Sunday Times, he was paid more than the top dogs at HSBC, Shell and BP last year. Shareholder advisory groups Pirc and Glass Lewis have urged investors to reject the businessman’s renumeration at the company’s annual general meeting on Thur…