I told you..,

[Marion Morrison]

There are two parts to it. Firstly the criminal activity around the funding and its links with Russia. Both leave campaigns are currently under investigation.
Brexit donor Arron Banks is referred to National Crime Agency | Daily Mail Online

Police probe Banks's Brexit vote spending

Arron Banks criminal investigation: could evidence against him make Brexit void?

Secondly the actual lies they told during the campaign. These articles gives a flavour.
11 Brexit promises the government quietly dropped

List of Brexit lies: an A to Z | British GQ

Its not just narrow definitions. The whole campaign was predicated on straight out trump style lying.

Why you throw Trump in there, like he has something to do with the EU?

 

[harmonica]

they never should've got into the EU
AND it's a monopoly against the US

 

[DOTR]

A chaotic Brexit is part of Trump’s grand plan for Europe | Natalie Nougayrède

 

[DOTR]

Are they this stupid? Or do they just think we are?

 

[DOTR]

Did any of you know that Ireland will become a wasteland if Brexit occurred?

 

[Tommy Tainant]

Did any of you know that Ireland will become a wasteland if Brexit occurred?

View attachment 250641

Why would you think that Northern Irish farmers would know anything about Northern Irish farming ? Its absurd.