Labour leader Keir Starmer is considering further watering down his party’s £28 billion green borrowing pledge in a bid to appear fiscally responsible, the Telegraph reported.

The opposition leader faces growing pressure from within Labour to reduce the cost and impact of the so-called green prosperity fund, a person from within the party who wasn’t identified told the newspaper.

The fund would see Labour borrow billions to invest in environmental jobs and industries, but some see it as potentially damaging to the party’s aim to get debt falling as a share of national income after five years.

“The fiscal rule matters more, and that will dictate how much is in the green prosperity fund,” the person told the Telegraph.

The latest potential watering-down of Labour’s environmental goals follows earlier row-backs on the green prosperity fund. Shadow Chancellor Rachel Reeves was forced to scale back the party’s plans in June, saying that rather than committing £28 billion ($35.3 billion) every year for five years from the start of a Labour term in office, the policy would ramp up by the middle of Parliament.

Some shadow cabinet members also have concerns over where the money will be directed, the Telegraph said, with some saying Labour hasn’t done enough to articulate its plans.