Barclays is facing a fresh revolt from the UK’s most powerful investor group amid mounting concerns over its role as the biggest European financier of fossil fuel companies.

The Investor Forum, which holds £18.5tn in assets and represents Britain’s largest investors, is understood to be pressing Barclays to adopt stricter policies on climate change before the bank’s annual shareholder meeting in May.

The bank is already facing criticism from a separate group of 11 pension and investment funds managing more than £130bn of assets. Spearheaded by the campaign group ShareAction, they have filed a resolution calling for Barclays to set clear targets to phase out services to energy companies that fail to align with Paris climate goals.

But the reported intervention of the Investor Forum, whose members include all the big names in the UK fund management industry, will intensify the pressure on the bank. The Investor Forum declined to comment.

Barclays is being targeted because of its leading role in funding fossil fuel projects. A recent study found that its lending and underwriting to carbon-intensive companies and projects between 2015 and 2018 totalled $85bn (£64bn). The sum is more than any other British or European bank, and prompted campaign group ShareAction to coordinate the resolution tabled for May’s AGM.

Barclays said: “We continue to engage with ShareAction and other stakeholders on this issue and will make a further statement at the appropriate time.”

Privately, the bank believes the campaign against it is unfair, pointing to figures that show that while it remains a significant banker to the fossil fuel industry, its business with the companies most aggressively expanding in the sector fell sharply, from $13.1bn in 2016 to $5.2bn in 2018. It has also facilitated £27.3bn in “green” bonds and renewable financing.

Unlike some European banks, Barclays has not ruled out funding projects or companies involved in coal or tar sands, regarded as particularly polluting as they require large amounts of energy to extract.

Barclays has faced protests in its branches from Greenpeace campaigners over its involvement in tar sands, focusing on the pipelines being built across Canada and the US to bring oil to market from Alberta’s tar sands.

If the AGM resolution is approved by shareholders, the bank will have to publish a plan to phase out the provision of financial services to energy companies that are not meeting Paris climate goals.

It is understood that since the pension and investment funds filed their resolution, the Barclays chairman, Nigel Higgins, has engaged with institutional investors. The Financial Times suggests the bank is considering putting forward its own climate change plan to stave off the investor revolt.

Barclays has a way to go before it meets the standards set by some other European financial giants. The insurer Axa said in 2017 that it was divesting from 25 tar sands companies as well as the three large pipelines needed to deliver their oil to market.

BNP Paribas, one of the biggest banks in France, has also pledged to stop financing companies whose main activity is extracting oil and gas from shale deposits or tar sands.

Biggest banks providing finance to fossil fuel extraction, 2015-18 total

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1. JP Morgan Chase $195.6bn

2. Wells Fargo $151.6bn

3. Citi $129.5bn

4. Bank of America $106.7bn

5. RBC (Canada) $100.5bn

6. Barclays $85.2bn

7. MUFG (Japan) $80.1bn

8. TD (Toronto Dominion) $74.1bn

9. ScotiaBank $69.6bn

10. Mizuho (Japan) $67.7bn

Source: Fossil Fuel Finance Report Card 2019