But last night Watson reminded us that even the party's so-called moderates have an instinct for blunt, authoritarian interventionism, and policies that are populist, childish and would ultimately prove counterproductive.
Responding to news that some banks and hedge funds have commissioned private exit polls in an attempt to understand the likely result of this month's EU referendum Watson reacted in the manner of confused anti-capitalists the world over – he called for it to be banned.
"I hope the government will put measures in place to prohibit this avaricious plan by financiers to benefit from information that belongs to every voter," Watson said.
His demand – that individuals and organisations should not be allowed to commission private surveys – is predictably illiberal, but also makes no sense. Just a few moments after insisting that hedge funds "stand to make many millions of pounds" from their polls, Watson describes polls as "often unreliable".
Exit polls are especially unreliable during elections with no recent and direct precedents. This is why, at this point in time, none are expected to be published on the evening of 23 June. Hedge funds, by nature, are comfortable with risk, and thus some think it is worthwhile to invest heavily in polling research in a bid to jump the gun and get a head-start on the rest of the market. However, you should be under no illusion – this is a considerable gamble, resting on an expensive outlay. If it was as simple as Watson suggests for "financiers... to make millions of pounds", then all the major banks and fund managers throughout the world would be getting in on the game.
Daring financial market punts on political outcomes are nothing new (and could be observed during the recent Greek crises, for example); as a niche pursuit, they are part and parcel of a healthy, free market in which prices reflect various degrees of information and interpretation.
The run-up to the referendum has seen many frivolous claims emanating from both sides of the debate, but Watson's complaint is perhaps the silliest of them all.