While the contest is too close to call ahead of the June 23 referendum, polls suggest one of the biggest divides when it comes to voting intentions is generational.
The latest YouGov poll found that 64 per cent of respondents aged 18 to 24 want Britain to stay in the European Union, while 24 per cent support a “Brexit,” or a British exit from the 28-country bloc.
The figures for respondents ages 65 and over are almost the opposite — 58 per cent of them support a Brexit, while 33 per cent want to stay in the EU.
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The website was created by 34-year-old London advertising executive Liam Brennan, who wanted to, "use the passionate, under 35-year-old audience - who are already posting about the EU referendum in their social feeds to people who already think the same way - and get them to try to sway the older segment, who still read traditional media and aren't exposed to a variety of sources and arguments beyond immigration and identity".
The site lists various reasons why Britain would be better off staying in the EU, offers a template script to use when speaking to your Nan, and suggests why she might be willing to change her mind.
"Your Nan, like a lot of Nans, will probably be voting to leave the EU," the website reads.
"Unlike you, she hasn't been able to go and find herself for a year in Berlin, know a crazy Italian guy who throws great house parties or knows what a tariff free single market is.
"If your Nan understood what being in the EU meant for her grandkids, then maybe she might be willing to change her mind. It's time for an intergenerational chit chat."
The #callyournan campaign has divided opinion on Twitter. Many have taken up the lead to get in touch with their grandparents and discuss the upcoming vote.
Other Twitter users found it disrespectful and patronising.
Meanwhile, Peter Downey, 73, allowed his 17-year-old grandson Freddie Wells to have his say in the referendum by voting on his behalf.
"Originally my grandad was going to vote leave in the EU referendum but then he came up to me and offered me the chance to persuade him and offer him my opinion on the decision that will be one of the biggest I'll ever have to make," Wells told the BBC.
"He realised it will have such a big impact on my life - more on mine than it will on his.
"We actually did the vote last night, I did a postal vote with him, and I crossed the remain box."