Kezia Dugdale, Scottish Labour’s deputy leader, has emerged as the clear favourite to take over from Jim Murphy after his abrupt resignation following the party’s humiliation in the general election.

Ian Murray, Labour’s sole remaining MP in Scotland and an ally of Murphy’s, told the Guardian he wanted Dugdale to take over as a leader, while she was also backed by two senior and influential MSPs who were prominent in the campaign to oust Murphy last week.

I think she’s fresh, she doesn’t carry any baggage of the past. She inspires people Ian Murray

“I just think she has been a good deputy leader; I think she’s fresh, she doesn’t carry any baggage of the past,” Murray said. “She inspires people. She’s really experienced at community engagement and local community activism, which is where the Labour party has to get back to.”

Signalling that Dugdale could quickly become endorsed as the unity candidate after a week of infighting, the MSP who opposed Murphy’s leadership and is a leading figure on the party’s left, suggested she could end up standing unopposed.

Speaking on condition of anonymity, he said: “My personal position is I would like to see Kez step up and I would like her to do that as quickly as possible; and there might not even be a contest.”

She was also endorsed by Alex Rowley, a former general secretary of Scottish Labour who resigned from Murphy’s shadow cabinet last week in protest at his refusal to stand down.

“I’m hoping Kez will put her name forward. She’s already our leader in the Scottish parliament and if she does, she will make an excellent party leader,” Rowley said.

Murphy resigned on Saturday only moments after defeating a no-confidence motion tabled before the Scottish Labour executive committee by a narrow 17-to-14 margin, after 10 MSPs signed a joint letter which called on him to quit.

The Sunday Herald reported that Murphy won after voting himself on the motion, which raised eyebrows, and that the issue was carried by the vote of life peer Meta Ramsay, a former spy.

Ramsay, an ally of Murphy’s, was put on the executive temporarily by interim UK leader Harriet Harman because, under party rules, there are two executive places for MPs. The general election rout meant there was only one MP in Scotland to take an executive seat.

Jim Murphy, pictured with Kezia Dugdale, resigned on Saturday. Photograph: Andrew Milligan/PA

Murphy said that a slender victory, and escalating attacks on his leadership from the left and union movement, showed the party was too deeply fractured after it lost 40 of its 41 seats to the Scottish National party at the election for him to remain in post.

Murray, who has been made shadow Scottish secretary under Harriet Harman’s interim leadership of the UK party, ruled himself out from the Scottish contest chiefly because he believed the next leader had to be from Holyrood. “If anybody thinks that the powerhouse in Scottish politics is not Holyrood, they must be barking mad,” Murray said.

After Labour’s catastrophic election result left it with just one Scottish MP, there are 38 MSPs in the Labour group at the Scottish parliament including potential challengers Alex Rowley, an ally of Gordon Brown and a former Scottish Labour general secretary, and Jenny Marra.

Murray’s endorsement was quickly followed by confirmation from Neil Findlay, who challenged Murphy for the Scottish leaders post last year, that he would not enter the latest contest despite being one of the first to urge Murphy to resign last week.

Findlay said in a statement he wanted to play a full part in the urgent quest to rebuild the party and its morale in time for the 2016 Holyrood election, “but I also want to make it crystal clear that I will not be a candidate in the election for the position of Scottish Labour leader”.

Dugdale is expected to take over as interim leader once Murphy formally resigns at a Scottish executive meeting next month, where Murphy will present a new strategy paper urging the party to introduce one-member-one-vote for Scottish leadership elections.

The executive is expected to debate and vote on Murphy’s proposed reforms, and agree a leadership election timetable to be presented by Brian Roy, the Scottish party’s general secretary.

As he lashed out at the “poison” of Len McCluskey, the Unite trade union leader, for blaming him for Labour’s defeat at the election, Murphy said the power of the unions in the Scottish party needed to be challenged. He said any leader backed by McCluskey would carry a political “kiss of death”.

Murray said he backed Murphy’s call for one member, one vote, which is already party policy for UK party leadership contests. Findlay, closely linked to the unions which attacked Murphy, refused to comment, however.

McCluskey hit back at Murphy on Pienaar’s Politics on BBC Radio Five live, and said he was being unfairly typecast as a “bogeyman” by Murphy. “I think, obviously, Jim is hurting and I can understand that. But he’s playing the same trick that rightwing media has played for a number of years, looking for a bogeyman as an excuse. I wasn’t the one who lost Scotland to the SNP,” he said.

McCluskey had opposed Murphy’s bid for the Scottish party leadership because he believed it would be a “political death sentence” for Labour if he took over since Murphy “has been at the epicentre of the ideology that has alienated the Scottish working class for years and years”.