This article was published in The Herald on Wednesday 1 April and is reproduced here with their permission.

Nearly half of voters across Great Britain believe that any greater influence that the SNP might have on the next UK government would be bad for the country as a whole, according to a new survey by TNS.

The poll of 1188 adults in Great Britain comes as opinion polls point to the likelihood of strong gains by the SNP in the May 7 general election, boosting its representation substantially from its current six MPs.

The Conservatives, with whom the SNP has pledged never to form an alliance, have strongly attacked Labour, claiming that it could form a government supported by a party that wants to “break up Britain”. Ed Miliband has ruled out a coalition – which Nicola Sturgeon has said would not have been an option anyway – but has not closed the door on an informal arrangement.

Asked whether the SNP having a greater influence in the next UK government would be positive or negative for the UK as a whole, 46% said it would have a negative impact, against 22% who thought it would be positive.

Opinion is strongly divided by age group, with older people generally hostile to the idea of more SNP influence at Westminster, while younger people are more relaxed: 64% of those aged over 55 believe that greater SNP influence would have a negative impact on the UK compared to 14% who are positive to this idea. By contrast, those aged 18-24 are positive towards the idea by 40% to 23%, while opinion in the 25-34 age group is evenly split (31% positive vs 30% negative).

Those in the middle age groups of 35-54 are more inclined to see greater SNP influence as having a negative impact on the UK – 42% compared to 21% who would see this in a positive light.

This partly reflects the fact that older people are more likely than the young to support the Conservatives, who have been outspoken in opposing SNP influence. However, the gap is wider in this poll than in voting intentions generally – the latest TNS polling on voting intentions in Great Britain suggests that the over-65s are around twice as likely to vote Conservative as the 18-24s.

Conservative supporters are substantially more likely than Labour supporters to see SNP influence as negative (72% vs 41%). This may partly reflect the more antagonistic tone of Conservative rhetoric towards the SNP, but it may also underline how many Labour voters see the SNP as potential allies – formally or informally – in helping Ed Miliband over the 10 Downing Street threshold.

We also asked respondents what the best outcome for the UK would be in the event of Labour potentially making an agreement with the SNP if the election results in a hung parliament.

More than a quarter of respondents favoured some arrangement between the two parties. Only around one in 10 backed the idea of a coalition between Labour and the SNP, which has in any case effectively been ruled out by both parties. A further 17% wanted a minority Labour government buttressed by an informal agreement with the SNP on specific issues. However, 41% thought that neither outcome would be good for the country, including 74% of Conservative voters.

A majority of Labour voters favoured an arrangement – 23% were pro-coalition and 31% supported a less formal arrangement – with 26% saying neither outcome would be good for the UK.

Again, there was a generation gap in attitudes towards an agreement between SNP and Labour: 61% of over-65s said neither outcome would be good for the UK, compared with 18% of the 18-24 age group. One in six of those aged 18-34 were in favour of a coalition, against 8% of those aged 55 and over.

Among the 105 people in Scotland included in the total sample, 23% favoured a coalition and a further 23% backed a minority government with an informal agreement between Labour and the SNP on specific issues, with 27% saying that either outcome would be bad for the UK. These figures may simply reflect the current level of support for the SNP in the polls in Scotland.

We also asked respondents how much of an impact, if any, they expected the results of the vote in Scotland to have on their own lives. Around half (52%) said it would have an impact, including 27% saying it would have a big or fairly big impact, while 30% said it would have no impact. Men were more likely to say it would have some impact (59%) including 33% saying it would have a big or very big impact.

Apart from voters in Scotland, those aged 18-24 and those intending to vote Labour were most likely to believe that Scotland’s election results would have an impact on their lives.

The poll results suggest that the issue of potential SNP influence in government is of real concern to voters across Great Britain. It also underlines how last year’s referendum campaign has raised the profile of Scottish politics across the UK: there is no polling data from previous general elections on how the rest of the UK views the electoral situation in Scotland, but it seems unlikely that the Scottish vote would have been such a subject of interest in the past.

The survey also suggests that the SNP has much to do to convince voters outside Scotland that it can be a constructive force at Westminster. That would also seem to be in Labour’s interests. Otherwise, the “SNP factor” could work to David Cameron’s advantage, handing power to the one party with which the SNP has said it will not do business.