This claim is accurate. Although the Sinn Fein manifesto didn’t declare the exclusion of “don’t knows”, this revises a 45/46/9 split to a rounded 49/51 split between staying in the UK and leaving the UK and joining the Republic of Ireland.

UPDATE: A previous version of this article applied a survey from Ashcroft Polls from May/June 2018. This updated version uses a more recent Ashcroft Poll from September 2019. The result is a change of conclusion from INACCURATE to ACCURATE.

In their 2019 Westminster election manifesto, Sinn Féin claimed the following in section, “Looking to the Future”:

In a recent opinion poll in the north carried out on behalf of the Tory peer, Lord Ashcroft a majority of those polled said that if there was a referendum on Irish unity tomorrow, they would vote in favour of unity.

Lord Ashcroft published the following graphic on Twitter, which shows 51% response “for Northern Ireland to leave the UK and join the Republic of Ireland” and 49% response “for Northern Ireland to stay in the UK”. The graphic includes a statement that “figures shown exclude those who answered ‘don’t know’ or ‘would not vote’”. This qualifying statement was not published in the Sinn Fein manifesto.


Lord Ashcroft Polls

The figures are cited from a survey by Lord Ashcroft, where 1,542 adults in Northern Ireland were interviewed online between 30 Aug and 2 Sept 2019. Results were weighted to be representative of all adults in Northern Ireland.
One of the survey questions was, “If there were a ‘border poll’ tomorrow, how would you vote?” The responses are shown in the following table:

For Northern Ireland to stay in the UK45%
For Northern Ireland to leave the UK and join the Republic of Ireland46%
Don’t know9%

Excluding “Don’t knows”

Firstly, it is incomplete to quote a percentage for a smaller number of options without acknowledging that fewer options are being taken into account than were captured in the poll or survey.

Nevertheless, excluding the “don’t knows” enables one to say “for those who expressed a preference”,  49.45% chose the option “for Northern Ireland to stay in the UK” and 50.55% chose the option “… join the Republic of Ireland”. Rounding up these figures to the nearest per cent results in a 49/51% split between staying or leaving the UK.

Other polls

The online blog, Northern Slant, published an article that reviewed a previous Ashcroft survey as well as three others that asked people their voting intention in a referendum on the constitutional status of Northern Ireland: “What do the latest polls tell us about Northern Ireland’s future?”

The four surveys were:

  1. Queen’s University Belfast (polling by Ipsos-MORI)
  2. BBC (polling by LucidTalk)
  3. Northern Ireland Life and Times survey
  4. Lord Ashcroft Polling

The results are summarised in the following graphic, which includes “undecided/don’t know” respondents:


The more recent Ashcroft Poll survey (September 2019) is significant in that it shows a majority support for the option for “united Ireland”.


In its manifesto for the 2019 General Election, Sinn Fein made a statement and published a graphic that claimed there was 51% support for Northern Ireland to leave the UK and join the Republic of Ireland, without declaring that there were “don’t know” responses.

An analysis of the cited Ashcroft Poll (September 2019) shows a 45/46/9 split between staying in the UK, leaving the UK, and “don’t knows”. Excluding the “don’t knows” results in a rounded 49/51 split between staying in the UK and leaving the UK and joining the Republic of Ireland.

Image: Photo by Chris Dorney used by license

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