AN SNP activist who wants to oust Labour’s sole MP in Scotland hopes a three-way split in the Unionist vote in the key marginal constituency will help his party win the seat.

Businessman Doug Thomson was the first potential candidate to come forward to take on Murray in Edinburgh South.

The fund manager could face former MSP Jim Eadie as a rival in the party’s internal selection process.

Well known in the area, Eadie lost his Holyrood seat at last year’s Scottish Parliament election and is currently believed to be considering whether to stand for Westminster on June 8.

Members of the SNP’s ruling National Executive Committee meet this weekend to decide on the process of selecting candidates. Given the tight timescale, it is likely the party will opt to select candidates by an interview panel, possibly as early as Sunday.

Thomson is married to political journalist Mandy Rhodes, editor of Holyrood magazine, and has lived in the Newington area of the constituency for six years.

He has missed out previously in internal party selection contests, notably to Bill Walker, the former Fife SNP MSP who was subsequently convicted of domestic assault and jailed, and Neil Hay, who was defeated by Murray in Edinburgh South last time round by 2637 votes.

He is hoping for success this time.

Thomson said: “There is very much a split on the Unionist side in the constituency. Ian Murray relied on Tory supporters voting tactically last time to get it.

“He faces a problem in that both the Tories and the LibDems are standing against him. The LibDems are trying to fight back in an area where they have been represented before in the Scottish Parliament.

“This factor could be helpful to us. Not only do we want to maintain our vote, we also want to persuade more people, who perhaps supported Ian Murray last time, to support the SNP.”

It is not clear yet whether the Scottish Greens, who came fourth in 2015, will stand again. Patrick Harvie’s party took 2090 votes two years ago, but the Greens have been focusing their election efforts on getting more seats at council level; currently, they have five councillors in Edinburgh.

The LibDems, meanwhile, came fifth in the seat at the General Election in 2015 with 1,823 votes, but the party hopes to increase their support on the back of its anti-Brexit stance in the strongly Remain-voting constituency.

Thomson hopes the Greens won’t stand in the constituency, perhaps in part because many of their student supporters in the area will have returned to the family home for the summer break by the time June 8 arrives.

“It would certainly help us if we could get support for Green pro-independence supporters,” Thomson said. "We could do with the extra vote.

“There is a risk they could lose their deposit if we get a good level of backing behind us in terms of the independence support.

“It’s whether they have the resources to target seats at short notice and with a lot of students already gone home for the holidays by then, clearly they won’t lose their deposit.”