A CANDIDATE in the SNP depute leadership contest believes his party should consider including European Union membership in any referendum question on independence.

Alyn Smith, a Nationalist MEP, said “all options” on the wording of any future ballot proposition should be discussed.

It has also emerged that SNP veteran Jim Sillars is backing a councillor for the post, as a way of taking power away from parliamentarians.

However, pro-independence supporters suffered a setback yesterday after a new opinion poll showed majority backing for Scotland staying in the UK. A YouGov poll found that there a Brexit exit decision has not triggered a boost in independence, with 53% still opposed.

Four candidates are expected to contest the race to succeed Stewart Hosie as the party’s number two: SNP Westminster leader Angus Robertson, fellow MP Tommy Sheppard, Smith and councillor Chris McEleny.

The internal election is expected to give the candidates a platform to discuss a second referendum, described as “highly likely” by First Minister Nicola Sturgeon as a result of Brexit.

One of the issues being discussed by SNP members is the wording of the question in the event of a second plebiscite.

In 2014, voters were asked: “Should Scotland be an independent country?”

However, a minute of the Yes Edinburgh West group noted that former SNP candidate Toni Giugliano floated an alternative.

It stated: “He proposes that if IndyRef2 happens, the question should be 'Should Scotland remain in the EU as an independent country?'"

Giugliano will speak at a debate at the SNP conference and is expected to suggest the new wording to delegates.

Smith, an SNP moderate who has spoken of the need of reaching out to the 55% who voted No in 2014, said of the plan: “It is certainly worthy of discussion and consideration. The options over the wording are open. Let’s look at all the options.”

However, Sheppard, who launches his campaign this week, is sceptical of the idea: “I think it might cloud the issue. I think it would be better to ask a question on independence.”

At his launch in Edinburgh last week Robertson, who is considered to be the favourite to win, also stressed the importance of listening to No voters.

Speaking to the Sunday Herald, he refused to be drawn on the timescale of a second referendum and dodged the question on the wording on the ballot.

He said: “I’m not wanting to be unhelpful, but we need to go through a process one step at a time. The First Minister and her council of advisers are trying to understand all of the options. I would prefer to concentrate on supporting that process.”

However, a parliamentarian said of Robertson’s depute leadership bid: “Angus’ bid is about shoring up his position in the SNP group. I think that is what is driving absolutely everything.”

Asked whether former SNP leader Alex Salmond is supporting him Robertson said: “From day to day I’m receiving support from elected colleagues and grassroots colleagues. I think you can see everybody who has declared publicly for me so far.”

Sillars, an SNP grandee who was once deputy leader himself, entered the fray with a surprise endorsement of McEleny.

The Inverclyde councillor is considered to have little chance of winning, but Sillars said: “There is a grave imbalance now in the SNP. My support of the councillor is saying ‘he represents the need to rebalance the power within the SNP between the party as such, and the parliamentary groups’.”