The rise from nowhere of Chris Huhne has been difficult to quantify. Where YouGov polls called the Tory leadership right and early, such a repeat has been harder for the Lib Dems, not least because no-one knows who the members are. Accordingly, the only real indication of who's up and who's down has been the betting markets. These showed a surprising and steep rise in support fro Huhne, mainly at the expense of Ming Campbell.
The markets, being the only reflection of intention, have therefore played the role that polls usually do, providing candidates with the most important asset of all: momentum. So, why the conspiracy? Well, Huhne rose really very fast, from nowhere, to become favourite. On two occasions (after Question Time and Newsnight) when Ming was seen to do well, heavy bets were put on Huhne and against Ming, which 'rectified' the odds (see fig.)
Conclusion? Maybe the markets can be manipulated by someone prepared to spend enough money - didn't Huhne say he didn't know if he was a millionaire? Maybe he's waiting to see if his bets come off...