It seems to me the mandate for Brexit, such as it is, can only derive from either or both of two events, namely the referendum of 2016 and/or the General Election in December 2019. So what are the relevant figures?
The 2016 Referendum
The question asked was
Should the United Kingdom remain a member of the European Union or leave the European Union?
with the responses to the question to be (to be marked with a single (X)):
Remain a member of the European Union
Leave the European Union
The Results were as follows (source Electoral Commission):
|Leave the European Union||17,410,742||51.89|
|Remain a member of the European Union||16,141,241||48.11|
|Invalid or blank votes||25,359||0.08|
|Registered voters and turnout||46,500,001||72.2|
Yes some 1.3 million more people voted Leave than Remain. But that equates to 37% of eligible registered voters who voted in favour. The UK adult poulation in 2016 was 64.6 million according to the Office of National Statistics so there are approximately 18 million unregistered potentially eligible voters. So its some 26% of total potential electorate who voted leave. Excluded from eligibilty were 16-18 year olds and EU and citizens resident in the UK (unless from Ireland, Malta or Cyprus), all of whom were eligible to vote in the Scottish Independence referendum. Commonwealth citizens resident in UK were eligible to vote.
THE 2019 GENERAL ELECTION
The results were as follows
|Party||MPs||Number of Votes||% votes|
|Democratic Unionist Party||8/650||244,128||0.8%|
|Alliance Party (NI)||1/650||134,115||0.4%|
Which if you study it shows just how bizarre the UK system is. Lots of anomalies- eg the SNP with 1.2 million votes get 48 seats while the Lib Dems with 3.6 million votes get 11 seats. The Brexit Party with 644,257 votes get no seats while the DUP with 244,128 votes get 8 seats.
Total votes cast were 31,829,630 and total number of registered voters were 47,587,254. Conservative Party manifesto and Brexit Party policy were pro Leave so approximately 45% of actual voters or 30% of registered voters voted for parties that supported Brexit. Again there will be some 18 million eligible adults not registered so as a percentage of total potential electorate its 22% who voted for pro Leave parties. Its not really possible to derive a sensible figure for how many voted for pro Remain parties given the Labour party’s ambiguous position on the issue.