Kent County Council is under fire after it was revealed its pension fund has invested £165.5 million into companies associated with fracking.

The figures, obtained by campaign group Platform London, come as fracking is set to resume in the UK for the first time in seven years.

Councillors at the authority have been advised against sharing their position on the issue in an internal email seen by KentOnline.

KCC invests 3.7% of its workers' pensions in companies that frack.

It comes amid continued opposition to the controversial process, which supporters argue can create jobs and tax revenue while lowering energy bills.

Fracking is a process of extracting oil or gas which involves injecting liquid at high pressure into subterranean rocks, which many argue can cause soil pollution or cause earthquakes.

In November 2013, four Kent sites were considered as potential sources of shale gas, receiving a mixed response from both council members and local people.

Fracking firm Caudrilla, which is set to begin drilling near Blackpool this summer, has now thrust the topic back into the national spotlight.

County councillor Martin Whybrow (Green), who represents Hythe West, said: "I believe that pensions and investments should be decided based on ethical as well as financial concerns.

"I am opposed to all councils holding shares in fossil fuel companies, and there is no excuse for KCC's investment in tobacco firms.

"We have an environmental strategy, which talks about needing to tackle climate change, yet we are supporting companies that are extracting fossil fuels."

Hydraulic fracturing, or fracking, is the process of drilling into the earth to recover gas and oil from shale rock.

A high-pressure water mixture is directed at the rock to release the gas inside, and can be carried out by drilling both vertically and horizontally.

The term fracking describes the way in which the rock shatters as the process is completed.

Peter Oakford, KCC’s deputy leader and cabinet member for finance and traded services, said: "The council’s pension fund is managed independently of the council itself by external investment managers who have the responsibility to get the best return for organisations and individuals – including the pension holders and their families.

"All matters relating to the management of the fund are the responsibility of the Superannuation Fund Committee which has a responsibility to maximize investment returns for a given level of risk.

"The amount invested in the companies on this list is about 3% of the £5.8 billion invested in the fund.

"The public will be familiar with the names of the bigger companies on this list and it is clear that they derive most of their revenue from activities that have nothing to do with fracking.

"In fact, none of the companies on the list of investments is among the UK’s top fracking companies.

"We expect the external investment managers to invest in companies with good standards of corporate governance as well as producing the best investment returns."

Sakina Sheikh, divestment campaigner with Platform London, said: "The devastating fires and record temperatures this summer have brought the impact of climate change home.

"Neither local communities or our climate can afford for the fracking industry to win.

"Our councils are providing everyday support to the frackers, it’s time to stop. It’s time to divest from fossil fuels."