Scottish investors are being offered a unique opportunity to use their Isa saving to benefit charities of their choice in a 'you give, we give' investment.

The Charities for Scotland Isa was launched at an event at the Scottish Parliament attended by national and local charities, leading Scottish fund managers, and potential investors.

Its creators believe it will play into the growing demand for socially aware investing, and are also working on the first 'ethical pension' product which they believe could appeal to new ­workplace savers under auto-enrolment.

The Isa is the brainchild of Edinburgh-based Virtuo Wealth Management and London-based employee-owned wealth specialist Tam Asset Management.

It enables investors to sign away a chosen percentage of any annual returns they make to their chosen charity.

TAM Ethical will then guarantee to match that by donating the same percentage of its annual management fee to the same charity. Donations can be gift-aided, they may be eligible for tax relief, and investors can change their charity or opt out at any time.

Scott Murray, founder of Virtuo, said: "We are trying to encourage investors into the ethical investment market, but trying to partner with charities where we can donate some of the growth potential available and pass it on tax-efficiently.

"Since the financial crisis we have started to think 'how much growth is enough, if portfolios make 10% is that enough?' Rather than asking people to dip into capital, why not ask them to take it out of income?"

Mr Murray, an accountant who started the firm when he became "disillusioned about the sector," added: "We all try to shop organically and locally, I think we have to look at investment ethically or at least consider starting off with a percentage.

"It is not dotcom small companies, we are talking about large-cap companies with track records of profitability, and there are very attractive potential returns out there."

Lester Petch of TAM Ethical said the concept of 'if you give a bit, we give a bit' was a powerful one, and the managers hoped to work with small- and medium-sized charities which most needed help.

He added: "We are working with the pension sector to create a socially responsible and ethically minded pension where charities can also benefit. We are moving into an era where charitable contributions from the financial sector can increase and should increase.

"This is going to build into something quite dynamic but it is going to be a slow burn."

Mr Murray said: "We are trying to make a socially responsible auto-enrolment package for charities, as they should be considering such pension schemes for their own organisations."

TAM Ethical offers five risk-rated portfolios, for which it chooses funds from the 120 in the market.

Mike Appleby, manager at Dundee-based Alliance Trust's Sustainable Future funds, said: "We believe companies that work against the broader society ultimately will not do as well as those who are working with society. We believe more sustainable companies make better investments and we are trying to generate returns that are better than the conventional market."

He said many funds in the sector had outperformed the market over the past three, five and seven years despite testing conditions, and fees were in line with other funds.

Ryan Smith of Kames Capital in Edinburgh, which has one of the oldest and best-performing ethical equity funds, said: "We are conscious that the financial sector in general probably has quite a lot to do to rebuild trust in the industry, one of the things we can do is try to make sure companies are run in a proper manner." He noted the important recent ruling by the Law Commission that charity trustees could and should consider social, environmental and governance issues when investing.

Questioned by The Herald on charges, Mr Petch said he expected the funds would have a total expense ratio of 1% to 1.2% which was a "very low price".

Mr Murray said: "We are very keenly costed. Financial companies have charged rather a lot, the good thing after the financial crisis is that charges have been taken down to a more appropriate level."

Colin McLean, founder of SVM Asset Management which runs a successful SRI fund, commented afterwards: "I think it is encouraging that Scotland is getting the launch, that they have engaged with Scottish charities and Scottish investment managers, and I hope it engages with Scottish investors too.

"It is an innovative product, it seems simple but it is administratively complex. There is no reason why it should not be successful."

The partner charities signed up to the scheme are Yorkhill Children's Charity, Capability Scotland, Edinburgh Cyrenians, Bethany Christian Trust, and 500 Miles, which works to provide prosthetic and orthotic devices for people in Malawi, Zambia and potentially Zanzibar. But investors can choose any registered charity for their donations.