The Government must never again “bluff” with a referendum and fail to plan for a shock result like Brexit, MPs have warned.
Instead, it must prepare for the outcome it opposes - such as Britain voting to leave the EU - and avoid being unready to act, the cross-party parliamentary report said.
Better planning could have helped David Cameron survive his Brexit defeat, the Public Administration and Constitutional Affairs Committee suggested, but instead his “credibility and authority were undermined”.
Cameron resigned within hours of 52% of those who voted voting to leave the EU. In the days after the vote it became clear the Government had not planned how to actually do this.
“In other countries, referendums are not conducted on the basis that a Prime Minister must resign in the event of losing a referendum,” the committee noted.
“A more responsible conduct of the Government’s case in the run up to the referendum, and proper planning for a Leave vote, would not have opened up so much new controversy.”
It continued: “Using a referendum as a ‘bluff call’ in order to close down unwelcome debate on an issue is a questionable use of referendums.
“Indeed, it is incumbent on future Parliaments and governments to consider the potential consequences of promising referendums, particularly when, as a result, they may be expected to implement an outcome that they opposed.”
The committee also said the way the Treasury presented its reports during the referendum suggested bias and called the decision to spend £9 million sending pro-Remain leaflets to every home “inappropriate and counterproductive”.
Civil servants were told not to brief Leave-backing ministers on issues relating to Brexit. The committee’s report said the Civil Service “should never have been asked to operate in a climate where contingency planning [for a Leave vote] was formally proscribed”.
All this increased “public distrust” in civil servants, the committee said as it warned the Scottish Government not to repeat these mistakes if it holds a second independence referendum.
After Scotland’s 2014 referendum, the same committee recommended a change to the Civil Service Code to clarify how civil servants should behave when the Government takes a position in a national poll.
But the UK Government rejected this.
The Scottish Parliament voted for a second independence referendum in March but Westminster responded saying now was not the time for one as Britain begins to leave the EU.
Committee chairman Bernard Jenkin said: “The use of the machinery of government during referendums has a significant effect on public trust and confidence.
“Referendums, therefore, need to be designed in such a way as to provide the utmost clarity for parliamentarians, campaigners and, above all, the electorate.
“It is of the highest importance that the referendum process is seen to be fair, by both sides, and that the result is agreed to, even if not with, by both sides.”
Labour’s Paul Flynn, who was the only MP on the committee to vote against the report, warned that “referendum outcomes are decided by the side that tells the most convincing lies”.
He also blasted that: “Use of algorithms and artificial intelligence was probably a significant but invisible element in the campaigns but is dismissed in the report.”
Flynn added: “There is an absence of evidence of Russian cyber influence or other invisible campaigning from other countries. This may be because the Electoral Commission has not investigated.”