The official story is that the referendum taking place in the UK today will not have exit polls, which are banned.
As The Telegraph points out, however, YouGov is carrying out on-the-day polling and will release its results at 10:00 PM local British time. Here’s the explanation from The Telegraph:
Will there be an exit poll?
Technically, no. An exit poll is conducted on a large scale outside polling stations but broadcasters have no way of knowing how accurate an exit poll would be as the last result they have to compare it to is the 1974 referendum. However, pollsters YouGov will be running an on-the-day poll on June 23, the results of which will be announced at 10pm, once voting has closed.
If you’re curious as to who YouGov is, here are the opening paragraphs of the Wikipedia entry on them:
YouGov is an international internet-based market research firm, headquartered in the UK, with operations in Europe, North America, the Middle East and Asia-Pacific.
YouGov was founded in the UK in May 2000 by Stephan Shakespeare and Nadhim Zahawi. In April 2005, YouGov became a public company listed on the Alternative Investment Market of the London Stock Exchange.
Stephan Shakespeare has been YouGov’s Chief Executive Officer since 2010. Roger Parry has been YouGov’s Chairman since 2007.  Political commentator Peter Kellner was YouGov’s President until he stepped down in 2016. 
YouGov is a member of the British Polling Council.
For those too busy to use the links above, here’s the basic information on YouGov’s founder Stephen Shakespeare (real name Stephan Kukowski, born in Germany of a German father who was the press liaison officer for the British Army of the Rhine; Kukowski took his present surname on marrying Rosamund Shakespeare), again from Wikipedia:
In 2012, Shakespeare was appointed as Chairman of the Data Strategy Board (DSB), the advisory body that was set up by the government to maximise value of data for users across the UK. In October 2012, the Department for Business, Innovation and Skills and Cabinet Office ministers announced that he would lead an independent review of Public Sector Information; the “Shakespeare Review: an Independent Review of Public Sector Information” was published in 2013. He is currently a member of the Government’s Public Sector Transparency Board and a trustee of the National Portrait Gallery, London.
He is the former owner of the websites ConservativeHome (now owned by Lord Ashcroft) and PoliticsHome (now owned by Dods Parliamentary Communications Ltd) which he launched in April 2008 after closing down his Internet television channel 18 Doughty Street.
He was named one of the Top 20 Most Influential People in Politics in the Debrett’s 500 2015.
With YouGov doing its on-the-day polling, it’s impossible to know where exactly they’re doing their surveys, which of course makes this much harder to pin down than a genuine exit poll.
Instead of a properly run exit poll, on the day of the referendum which is to decide its political future, the UK public is being fed information from a survey carried out by a company founded by a German-born Conservative who sits on a number of government boards and whose company is conducting an in effect unofficial poll the details of which cannot be tracked.
Isn’t EU-style democracy a lovely thing indeed?