YES Scotland last night admitted losing a second member of its self-styled "top team" amid persistent rumours – vehemently denied – of cash problems at the organisation.

The cross-party movement for independence confirmed former RBS manager Jacqueline Caldwell had quit after just six months as its linchpin director of operations.

Caldwell's job description was to lead the day-to-day operations of the Yes campaign and ensure its policies were being implemented and goals achieved.

Since its launch 13 months ago, Yes Scotland has failed to move opinion polls in its favour.

Caldwell was also in charge of budget controls, board meetings and deputising for the chief executive in his absence.

Hired on a two-year contract last September, Caldwell resigned in March, but Yes Scotland did not publicise the fact. The organisation said Caldwell left for personal reasons but refused to elaborate.

Despite Caldwell's pivotal role, her post has not been replaced, and her duties have been shared out among other employees.

Yes Scotland has now lost half of what it called its "top team" of four directors.

Director of communications Susan Stewart left last week in a "streamlining" operation at the campaign's Glasgow HQ. Like Caldwell, she will not be replaced, with Yes Scotland chief executive Blair Jenkins taking a greater role in the media operation.

Director of communities Shirley-Anne Somerville and director of marketing Ian Dommett remain in post.

Announcing Stewart's exit, Yes Scotland said a review of its operating structure had led it to concentrate more resources into local campaigns to achieve a Yes vote next year.

Insiders say this is code for trying to get by with less money than expected. Despite receiving more than £1.6 million in declared donations, several sources in the Yes camp raised finance worries with the Sunday Herald.

A senior SNP source said: "There's no money coming through the door, just dribs and drabs."

The Sunday Herald first revealed financial tensions at Yes Scotland in February, when it emerged that, despite the SNP hinting it would forward two £1m donations, the party had held back most of the money for itself. The SNP ultimately passed on just £342,000 to help Yes Scotland's start-up costs.

Although Yes Scotland had £1.3m in other donations, almost all of this came from five established SNP donors, including £1m from EuroMillions winners Colin and Christine Weir, suggesting a limited donor base.

The pro-Union Better Together campaign has declared £700,000 from various business owners, and claimed to have received £1m more.

Yes Scotland has had significant outlays. Its showpiece office on Hope Street in Glasgow costs more than £70,000 a year to lease, and underwent an expensive fit-out.

It also had an initial outlay on stock for its merchandising operation, but much of what it tries to sell is unusually expensive for a political campaign, including £330 gold cufflinks and £9 reusable hot drink cups. Its best-selling items – pens, badges and stickers – are all £2 or less.

A Yes Scotland spokesman said reports of money problems were a misunderstanding. He added: "Ms Caldwell resigned from Yes Scotland in March this year for personal reasons. Her former role of operations director has not been filled and her duties have been reallocated among other employees."

A Better Together source said: "To lose one director could be put down to bad luck, to lose two could be considered careless. The Yes camp is being asked to do the impossible – sell something to Scots that they don't want. Little wonder people in Hope Street think the time is right to 'consider other opportunities'."