I believe that the Conservative Party's campaign at the last GE was based on scare-mongering and lies designed to undermine their opponents, rather than providing truthful information and involving open and honest debate in order for the electorate to make San informed decision for the good of the nation as a whole.

That just does not stand up.
Labour put their own case and attacked the Tory case.
Labour, Lib Dems, SNP and UKIP and the broadcasters would expose any "scare-mongering and lies" of the Tories.

The electorate of England is just not very left wing.
That does not mean that they must be exceptionally gullible, and easily hoaxed by "scare-mongering and lies."
You kid yourself.