All major political parties promised a referendum on the document. All three parties reneged on that promise. Labour claimed the Treaty was sufficiently different from the Constitution that it no longer had to keep the promise. The Conservatives still said they would have one, but if one closely analyses their conduct in the Commons they made much noise, but allowed the government to get away with cursory scrutiny. The Lib Dems changed the goalposts by arguing for an in/out referendum.

 

What became clear is that none of the political elites were prepared to ask the people.