Pledges made by SNP leadership contenders Humza Yousaf and Kate Forbes will cost the taxpayer up to £3 billion a year, raising questions about how it would be raised, say the Scottish Conservatives.

Ms Forbes has outlined commitments costing about £2.9bn, while Mr Yousaf’s bill would come to more than £1.6bn.

The Finance Secretary has pledged to deliver £15 an hour to social care workers at a cost of £1.8bn and said she would increase the Scottish Child Payment from £25 a week to £40, which Scottish Conservative research found would cost £265 million.

Health Secretary Mr Yousaf has committed to increasing the child payment by £5 a week, meaning he will need to find an extra £88m to fund that promise.

Two of his other key pledges – delivering universal childcare for one and two-year-olds and increasing funding for the Scottish National Investment Bank – would cost more than £1bn per year.

Daily Business first reported Mr Yousaf’s plan to raise funding for the bank from £2bn to £10bn on 5 March. He said he would fund it by asking the UK government for additional borrowing powers.

Shadow business minister Jamie Halcro Johnston said that the public will be alarmed as to how this extra spending would be delivered, given the SNP’s history of “wasting” taxpayers money.

He said: “This analysis reveals the eye-watering costs of the pledges made by Humza Yousaf and Kate Forbes when they can’t even keep on top of their finances now.

“From blowing over £300 million on ferries that are yet to set sail, the failed Rangers prosecution scandal, SNP ministers have continually been reckless with the public purse.”