Former Westminster leader Angus Robertson today said older voters, people born elsewhere in the UK and EU citizens in the Scotland are the key groups which are most sceptical about independence.

Robertson now heads up polling organisation Progress Scotland which is seeking produce research which will help make the case for independence.He told delegates during a fringe event at the party's Autumn conference that pro-independence campaigners must be alive to the sensitivities of undecided voters in a future referendum campaign.He cited the case of former European court of Justice judge Sir David Edward who came under fire from Nationalists online after posting a video explaining why his previous opposition to independence was shifting.

Pro-independence supporters have been urged to be "respectful"

"It is not an easy thing for people to change their mind when they thought that they were right and the other side was wrong," Robertson said."We need to empathetical and we need to be understanding and we need to be respectful and we also need to understand that there is not a killer answer that will see people change their minds overnight from a position of No to Yes with one number, one leaflet design, one fact, one turn of phrase."To start with one has to understand that emotionally you are welcoming the fact that people are on journey, that you are grateful people are prepared to be thinking about it and you express it in those terms."Pollster Mark Diffley has been working with Progress Scotland and said today a significant tranche of Scots are open to independence."About one in five people are undecided or open-minded - 20% of the population," he said.But he said this is split equally between Scots who voted both for and against independence in 2014, but are now wavering.

Scottish Independence: One fifth of Scots 'undecided or open minded' about leaving the UK