A Tory think tank behind a controversial call to raise the state pension age to 75 is being funded by one of the SNP’s most generous donors.

The Centre for Social Justice (CSJ), which faced an angry backlash over its pension proposal, has received up to £150,000 from tycoon Sir Brian Souter’s personal charity.

Founded as an independent think tank in 2004, the CSJ was set up by former Tory leader Iain Duncan Smith after he visited Easterhouse in Glasgow.

The organisation, which has strong links to the Conservatives, aims to put social justice “at the heart of British politics” and makes policy recommendations.

Strongly associated with the welfare reform agenda pursued when Duncan Smith was the Secretary of State for Work and Pensions, the CSJ describes itself as the “architects” of the universal credit policy. It was also supportive of the Tory Government’s benefits cap, which critics say has increased poverty.

The CSJ’s latest proposal was to suggest a rise in the state pension age to 70 by 2028, before another increase to 75.

It argued: “Working longer has the potential to improve health and wellbeing, increase retirement savings and ensure the full functioning of public services for all.”

However, the plan was denounced by opposition politicians who said older people faced being cheated out of their retirement.

It was also noted that the average life expectancy for men in Glasgow is around 73, raising the prospect of Glaswegians dying before they access their state pension.

In a motion at Holyrood, SNP MSP Sandra White said the plan would have a “disproportionate” impact on poorer people in Scotland and claimed it was a “further attack” on the elderly.

Image: Iain Duncan Smith

The Herald on Sunday has established that the CSJ, which does not publish details of all the donations it receives, has financial ties to Souter.

The businessman, who founded the Stagecoach bus empire, is a high profile Scottish Nationalist who has donated over £2m to the SNP.

He and his wife Betty also set up a charity, the Souter Charitable Trust, which focuses on projects that promote spiritual welfare and poverty reduction.

According to the SCT’s latest accounts, the Souter charity gave a £50,000 grant to the CSJ in 2018 and pledged another £100,000 as a future commitment.

Souter is an evangelical Christian who has used his money to promote independence as well as a range of socially conservative causes.

In 2000, he was criticised after spending around £1m on a nationwide referendum to oppose a gay rights measured backed by the then Scottish Executive.

In the past, he also met the SNP Government to discuss neuro-electric therapy for drug addicts and his charity has given £100,000 to an anti-abortion group.

Asked what the SCT funding was for, a spokesman for the CSJ said: “This funding helps support the CSJ which does research into the prevention and alleviation of poverty as per the charity’s and our own objectives.”

He added that the grant had not been been directed towards a specific paper or project.

Scottish Green MSP Ross Greer said: "In communities across Scotland the life expectancy isn't close to 75. This is a transparent Tory attempt to make ordinary people work until they die, rather than enjoy the retirement they have earned. It's no surprise that a reactionary like Brian Souter would fund an outfit like the CSJ.

"The SNP might want to use this latest opportunity to distance themselves from Mr Souter, given their repeated failure to do so previously."

The SCT did not respond to a request for comment.