"Referendums in the United Kingdom are very occasionally held at a national, regional or local level. National referendums can be permitted by an Act of Parliament and regulated though the Political Parties, Elections and Referendums Act 2000, but they are by tradition extremely rare due to the principle of parliamentary sovereignty meaning that they cannot be constitutionally binding on either the Government or Parliament, although they usually have a persuasive political effect.
Until the latter half of the twentieth century the concept of a referendum was widely seen in British politics as "unconstitutional" and an "alien device". As of 2018, only three national referendums have ever been held across the whole of the United Kingdom: in 1975, 2011 and most recently in 2016."
If the result of a referendum is not constitutionally binding on the Govt/Parliment, then why doesn't the govt just ignore the result & remain in the EU? Seeing how the UK hasn't got a clue on how to go about leaving the EU, and looks like it is going to lose a shed load of jobs if/when it does leave.