Sir Ronald Cohen, the co-founder of global investment giant Apax Partners, is not afraid of a little controversy now he has retired from active service at the firm.

In recent months he has called on his peers to pay more in tax, proposing an increase in capital gains tax on funds above £500 million. Then he grabbed the headlines again with a dire warning of potential social apocalypse as the gap between rich and poor widens.

If it were all just talk, some peers of Cohen say it would be difficult to stomach. But he has backed the talk with hard cash and, as non-executive chairman of VC pioneer Bridges Ventures, the private equity veteran can afford a smile of satisfaction. After all, it's hard to see Bridges as anything other than the industry's acceptable face of capitalism.

The five-year-old firm, which has a social mission, closed its second fund this summer on £75 million (€110 million; $147 million), 25 percent above its hard cap of £60 million and almost double the size of its first fund.

That £40 million 2002-vintage debut fund was invested in by the UK government's Department of Trade and Industry, whereas the new vehicle received no public sector support. The amount raised far surpasses the £20 million private sector investment in the prior fund.

Private sector investors clearly consider the firm a success – and Cohen's charitable trust will be among the beneficiaries if the firm delivers on its early promise.

Partly Cohen's brainchild, the firm is run by chief executive Philip Newborough. He says: “We have been successful for two reasons. We have recruited a fabulous team, who want more than just to make pots of money, and our investment strategy is sound.”

He says the firm is like any other venture capital firm but for the social screen it applies to investment opportunities. The business must help deliver economic and social regeneration to the most deprived 25 percent of the UK or it must show a strong social benefit in the areas of healthcare, education or the environment.

Michele Giddens, a director at the firm, says: “We have shifted mindsets with the first fund. It has broken down traditional notions, which were to maximise wealth and then to give it away in philanthropy. We have shown you can achieve social impacts and good returns.”

She said that although the firm had confounded sceptics, fundraising was still tough because investors found it difficult to know where to put such an allocation in their books.

Investors in the fund include banks and financial institutions, including: HSBC; pension funds; All Souls College, Oxford; investment group 3i; and Jon Moulton, founder and managing partner of private equity firm Alchemy Partners.

Bridges has had three exits to date: label business Harlands of Hull, which was sold to packaging company Clondalkin Group for £8.5 million with a money multiple of 3.5 times; lorry parts supplier HS Atec; and price comparison service SimplySwitch, its most successful deal to date, generating 22 times the original investment.

SimplySwitch underlines the firm's social project neatly. The site raised £500,000 for partner charities and created 80 jobs, mostly taken by unemployed women of ethnic minority origin.

Newborough, however, says it is important not to judge the firm's social return on a single investment. Instead, one should look at the aggregate effect, including five write-offs of early-stage investments. Taking this into account, the first fund is still around 50 percent up gross, before fees, he says.

In its efforts to demonstrate that social investing can also be profitable investing, Bridges Ventures appears to be making good progress.