The UK Government should become a partner in the Scottish National Investment Bank, former prime minister Gordon Brown has said.

The bank was set up by the Scottish Government to invest in companies that improve Scotland, create innovation or present solutions to reach net-zero - backed by an investment of £2 billion in its first decade.

Mr Brown, who served as chancellor before his time in Number 10, said the bank could be scaled up if the UK Government became a partner.

Speaking to reporters as he unveiled polling on the cost of living crisis commissioned by the Our Scottish Future think tank he founded, Mr Brown said bringing the UK Government into the bank could increase annual funding to £1 billion and help spur on the economy and counter the impact of rising costs.

"It makes sense for joint co-operative efforts to invest in these key areas and technologies," he said.

"Let's take the underfunded Scottish National Investment Bank. It has only £200 million a year to spend and yet far greater challenges than that for new investments.

"We should invite the UK Government to be an equal partner in the Scottish National Investment Bank, using all the resources of Britain to make Scotland an export superpower in renewables, life sciences, digital and manufacturing."

In a presentation, Mr Brown said the bank could also expand its operations, offering export guarantees and incentives to invest in Scotland, while also bringing in private venture capital firms to support its work.

Over time, he said, the model could be extended to allow Westminster to be a shareholder in regional investment banks across the UK.

The Scottish Government is currently the sole shareholder of the bank.

Meanwhile, the survey, carried out by Stack, found 47% of the 2,005 Scots asked said they would support a "serious plan to change Britain" over the country becoming independent, while 22% disagreed.

Mr Brown said: "Scottish people, clearly as our survey shows, prefer a plan for Scotland to deal with this crisis in which we mobilise all the resources of Britain through co-operating with Britain and to show that this co-operation can happen if the Scottish Government and ministers are prepared to make the effort.

He also again hit out at both the Scottish and UK governments for their response to the crisis, describing the decision by Scottish Finance Secretary Kate Forbes to effectively mirror the Chancellor's £150 council tax rebate for people in homes ranging from bands A to D as "failing on fairness".

He said: "When it comes to failing on fairness, the Scottish Government can't just blame the UK Government this time.

"For years they have pleaded for the right to do things differently and then immediately on having the chance to do things differently, they do the same as the Tories, both governments snubbing the poor."

The UK Government, Mr Brown said, should scrap plans to increase national insurance and bring back the £20 uplift to Universal Credit that was put in place during the pandemic and ended last year, while the Scottish Government should revisit the £150 rebate.