One of the most eminent academic institutions in the world, Cambridge University has an endowment fund (CUEF) of just under 3 billion pounds, the vast majority of which is invested indirectly through funds.

"Disengagement from any funds that have even small fossil fuel components, or that would require CUEF to step back from investments in alternative energy initiatives by global companies currently regarded as fossil fuel companies, would result in significant limitations on the CUEF’s ability to invest as successfully as in the past," Cambridge said.

Any weakening in the performance of the fund would mean less support to academic activities, it said late on Thursday, adding it had no direct investment in fossil fuel companies and wanted to avoid any direct investment in coal and tar sands, while keeping any indirect investment in those areas to a minimum.

Last year, Cambridge's principal governing body Regent House, including some 5,000 staff, voted in favour of full divestment from fossil fuels.

In April, about 350 Cambridge academics signed a letter to the university and its colleges, which are largely independent from the university's central administration and have their own investments, urging them to excise fossil fuel investments.

Signatories included chemist David King, who was Britain's Special Representative for Climate Change until last year after a seven-year stint as the government's Chief Scientific Advisor.

Shortly afterwards, BP Chief Executive Bob Dudley urged Cambridge University not to yield to pressure to cut its investments in fossil fuels and pointed to BP's donations to the university.

Cambridge Zero Carbon Society, a divestment campaign group, has called for the resignations of members of the University finance office, including Finance Director David Hughes, who formerly worked for BG, now part of Shell.

"Our managers often talk about ‘risk management’ and the importance of avoiding 'reputational damage'. It is hard to imagine a more risky, reputation-damaging moment in the history of the university," Mary Laven, a history professor, said in a statement via the Zero Carbon Society.

The world's top oil and gas companies are facing rising pressure from investors to shift to cleaner energy and renewables in order to meet international targets to sharply reduce carbon emissions by the end of the century.

(This story has been refiled to add dropped word in name of Cambridge Zero Carbon Society at first reference)

(Reporting by Shadia Nasralla; Editing by Edmund Blair)