Edinburgh, Scotland
A pro-independence rally in Edinburgh, Scotland. Reuters

With just three weeks to go before the referendum on Scottish independence, an ad designed to persuade undecided female voters to vote against separating from the United Kingdom has spectacularly backfired, with critics branding it “sexist” and “patronizing.” The ad has prompted many women who were previously undecided or planning to vote no to declare they will now vote yes.

The video, known as the "The Woman Who Made Up Her Mind," shows a working mother in her kitchen pondering her vote.

The video starts by making it clear that the fictional mother is undecided; she says she welcomes the quiet time away from her children in order to think, and that her husband will not stop bothering her to make up her mind. She says there are “only so many hours in the day” to make such an important decision, and then refers to Scottish First Minister Alex Salmond as “that guy off the telly.” In the end, after 2 minutes and 40 seconds, she decides to vote no.

The Scottish independence referendum, which takes place on Sept. 18, will ask voters one simple question: “Should Scotland be an independent country?" If a majority of Scottish voters opt for yes, Scotland will begin a two-and-half year period that will devolve power and sovereignty back to Scotland from Westminster.

Former Liberal Democrat MSP (Member of the Scottish Parliament) Margaret Smith, previously a known no voter, tweeted that the video was “absolutely appalling.” Former Liberal Democrat party convener Sandra Grieve also said the ad had convinced her to switch from no to yes. "When I watched it I felt like I'd been transported back to the 1950s," said Grieve. “I found it really shocking that we would portray a woman in 2014 who didn't know the name of Scotland's first minister and left all her political thinking for her husband to do."

A pro-independence group, Women for Independence, said it had been heard from many women who described the ad as "insulting, old-fashioned and unrealistic.”

Blair McDougall, the Better Together (i.e. no) campaign director, says that the words spoken in the video were “taken verbatim from conversations on doorstops with undecided women voters” and from the “opinion of women in dozens of focus groups around the country.”

The video prompted a backlash on Twitter under the hashtag #PatronisingBTLady.

While opinion polls have been tightening, it’s still projected that Scotland will reject the opportunity to become independent. A UK government commissioned You-Gov poll from Aug. 15 showed that no was winning 51 percent to 38 percent with 11 percent undecided. The Scottish Government-commissioned Panelbase poll from July 27 shows only a 7 percent difference with no on 48 percent, yes on 41 percent and don’t knows on 11 percent.

However, a recent debate between Alex Salmond, the first minister and leader of the Scottish Independence Party, and Alistair Darling, leader of the no campaign, may have shifted support: A snap Guardian poll on Monday showed that Salmond won the debate 71 percent to Darling's 29 percent.