The primary fundraising and political spending group supporting Donald Trump has spent more than $40m (£31m) on legal fees so far this year.

That money, due to be confirmed in a financial filing on Monday, has been used to defend the former president and his allies across multiple cases.

It is a more than two-fold increase in Save America’s spending on legal costs across 2021 and 2022 combined.

As Mr Trump’s legal battles intensify, the bills will only keep rising.

He awaits federal trial over his alleged mishandling of classified documents, state trial over a hush-money probe in New York, and a defamation trial from writer E Jean Carroll.

Meanwhile, the US Department of Justice (DOJ) and state prosecutors in Georgia are soon expected to charge Mr Trump, 77, over his efforts to overturn the 2020 election.

Save America is a political action committee, or PAC, founded and controlled by Mr Trump. His campaign manager Susie Wiles decides whose legal bills should be funded, according to the Washington Post.

It is funding representation for Mr Trump and those drawn into the various investigations against him who have requested help from his team, the Post reported.

That includes Walt Nauta, his close personal aide, and Carlos de Oliveira, the property manager at his Mar-a-Lago resort, who both face charges in the classified documents case.

The campaign has called it protection from “unlawful harassment”.

Spokesman Steven Cheung said in a statement that the DOJ “has continued to go after innocent Americans because they worked for President Trump and they know they have no legitimate case”.

Covering their legal fees, he said, will “protect these innocent people from financial ruin and prevent their lives from being completely destroyed”.

But the $40m sum far exceeds any other expense Save America has incurred during the 2024 presidential campaign.

And footing those legal bills, for the most part, are grassroots Trump supporters from around the country, whose small-dollar contributions make up the vast majority of Save America’s fundraising.

After leaving office, Mr Trump claimed that the 2020 election was stolen and urged supporters for months to back him up by sending to Save America.

Last year, he amassed over $100m in donations, using more than $16m to cover legal fees and about $10m on personal fees. His campaign and its supporters never proved widespread election fraud.

DOJ prosecutors sought information last year about how the PAC was formed and is operated, as part of their criminal investigation into the 2020 election.

At the start of his 2024 campaign, Mr Trump devoted only one cent of every dollar raised online to Save America.

But earlier this year, he began diverting a larger percentage – 10 cents of every dollar – away from the campaign and toward the PAC.

Jason Torchinsky, a campaign finance expert at the Holtzman Vogel Law Firm, said the candidate may be violating federal election laws by accepting donations that directly cover his legal expenses.

“It is not unprecedented for a campaign committee to pay legal fees,” Mr Torchinsky told BBC News.

“But the issue is that Trump is a federal candidate, with a third party to pay his legal bills, that really do amount to a gift to the candidate that exceeds federal contribution limits.”

National opinion polls show Mr Trump firmly in the lead to win the Republican nomination despite his mounting legal troubles, but some of his 2024 opponents have criticised the expenditures.

A spokesman for Mr Trump’s chief rival, Ron DeSantis, accused him of spending this year “on two things: falsely attacking Ron DeSantis and paying his own legal fees, not a cent on defeating Joe Biden”.

“He’s going to middle class men and women in this country and they’re donating $15, $25, $50, $100 because they believe in Donald Trump and they want him to be president again,” Chris Christie, another candidate, said in a June interview on CNN.

“They’re not giving that money so he can pay his personal legal fees.”

But Ohio Senator JD Vance, a Republican who has endorsed Mr Trump’s latest White House bid, defended the move on Saturday.

“I have good friends who did nothing wrong who had their legal fees paid by Save America PAC,” he said. “Would you rather they throw all of their employees under a bus?”

There is some evidence the escalating fees are putting a strain on Mr Trump’s political operation.

According to the New York Times, Save America has requested a refund on a $60m contribution it made to another group supporting Mr Trump. It is unclear how much of, or even if, the money was refunded.

Trump advisors are set to create a separate legal defence fund to handle legal costs for those entangled in probes of the former president, US media reported.

But Mr Torchinsky, the campaign finance expert, pointed out that, unlike in the case of Save America, such a fund will not require public disclosure of what is raised and where the money is going.

And with more indictments expected and preparation for trials imminent, he said: “I would expect the fees to go up exponentially.”

“It was $40m in the first half of the year. It wouldn’t shock me if the next six months rack up $60m.”