WINNING the case for Scottish independence will be the key focus of the contest to succeed Angus Robertson, according to senior SNP sources.

Party bosses are expected to announce the timetable for the internal election when they next meet at the beginning of March, with the new depute leader unveiled in June at a summer conference . It is understood such a schedule would see candidates in a Spring conference reboot arguments for autonomy and set out the strategies they believe could deliver a Yes vote in a new referendum.

The race will begin not long after the publication of the SNP’s growth commission report, due to be unveiled later this month, and which the First Minister has said will lay out her party’s new economic thinking to restate the case for independence.

“Clearly there won’t be much if any difference about the end point the candidates want to get to in terms of independence, but what each will have to do is set out the strategy they have about how they propose to win the argument for independence,” said one insider.

“There will be debates about how best the party can win majority support for its central proposition, how the party can relate to the wider Yes movement, what it should do to persuade people who voted No last time to move over to Yes.”

Chris McEleny, the SNP’s group leader on Inverclyde Council, was one of four candidates in the 2016 depute leadership which was won by Robertson.

Last night McEleny said he was reflecting on the contribution Robertson had made to Scottish politics and the independence cause.

He added: “The election deserves to be a contest of ideas and of course how to build a strong independence campaign. Someone should definitely be standing on a strong mandate for a second independence referendum in the timescale of this current parliament.”

How to achieve independence was among the subjects debated at the last depute leadership election but with little prospect of an imminent vote, attention was largely restricted to whether the EU vote would activate the 2016 mandate.

The forthcoming contest will take place against a very different background. It will take place a year after the First Minister set out plans to hold a new vote between autumn 2018 and Spring 2019.

Plans to introduce legislation in Holyrood were suspended after the SNP lost 21 seats in the snap General Election in June and the ongoing Brexit negotiations. Sturgeon has said she will update parliament this Autumn once the situation on Brexit is clearer.

Robertson stepped down as the party’s depute leader on Saturday, eight months after losing his seat, saying he was stepping down with immediate effect in order to pursue “new career opportunities”.

He was one of the SNP’s most high-profile losses in the June election, when he was ousted from the Moray seat he had held since 2001.

The First Minister expressed her “immense gratitude” for the job he had had done. He was already the SNP’s Westminster leader when he was elected depute leader of the party in October 2016, succeeding Stewart Hosie, who quit the role following claims about his personal life.

Since losing his seat in the general election, Robertson said he had been “focused on supporting campaign best practice for local SNP branches, constituency associations, elected members and the party nationally”.

But in a letter to Sturgeon he said: “I believe I am no longer able to fully discharge my mandate, which was to partner you as Westminster SNP Leader and as a parliamentarian representing a rural constituency.

“While it would be my greatest privilege to continue as Depute Leader, I know you understand that I have to focus now on pursuing new career opportunities. It is for that reason that I believe it is for others to step forward to seek the support of SNP members for the honour to serve as Depute Leader of Scotland’s largest political party.”

He added he was “tremendously honoured” to have held the role, and would now work to support public policy development in Scotland as an advisory board member of the Scottish Policy Foundation.

Sturgeon told the former MP he had “always been a source of wise counsel” to her, noting that when he was first elected to Westminster the SNP had just five MPs.

The party went on to win 56 of the 59 seats up for grabs in Scotland in the 2015 general election.