Mitt Romney will show his true colors tonight, when he slips behind closed doors in a foreign capital to collect money from international bankers who are mired in scandal.

The presidential contender is officially in London to cheer on the US team in the Olympics. But Romney doesn’t always cheer for Team USA. When it comes to global economics, Romney remains very much the “vulture capitalist” his Republican primary foes decried. And tonight, he’ll be swooping into central London to party with masters of the universe who know no country—and, it would appear, no ethical bounds.

London is abuzz over the Libor (London InterBank Offered Rate) scandal, which saw some of the biggest banks in the world report false interest rates in order to fool investors and game the international economy. Bob Diamond, the top man in Barclays Bank, had to resign from his position after that bank paid almost $500 million in fines.

Diamond also resigned as the co-chair of Mitt Romney’s $75,000-a-person fundraising event in London tonight.

Not to worry. Another Barclay’s insider (chief lobbyist Patrick Durkin) took Diamond’s place as a co-chair for the Romney event, along with officials of Bank of Credit Suisse, Deutsche Bank, HSBC, Goldman Sachs, Blackstone and Wells Fargo Securities—and, of course, Bain Capital Europe.

As the investigation of banks implicated in Libor rate-fixing expands, Romney’s decision to go ahead with the London fundraising events is an act either of boldness or recklessness. The presumptive Republican nominee for president seems to think he can get away with raising as much as $2 million at a series of fund-raising events held on foreign soil. The cheapest of Romney’s “lavish” London events has a $2,500-per-person entry fee, while the evening gathering where the most scandal-plagued of international bankers will mingle with their favorite American charges from $25,000-per-person to $75,000 a head.

That’s the kind of event that candidates like to keep secret.

But grassroots activists in the United States are upping the ante by demanding that Romney immediately reveal the names of the bankers and financial insiders attending his London fundraising events. In particularly, they are pushing for the release of any and all information relating to Romney’s interactions with donors associated with Barclays and any other institutions that have been linked to the Libor scandal.

The Center for Responsive Politics identifies Barclays as the largest source of campaign donations to Romney, and a Maine state legislator who has been in the forefront of campaign finance reform and corporate watchdog fights wants to know more about the relationship between Romney and the Barclays donors.

“Americans have a right to know who Romney’s donors are so they can understand what policy agendas are in line with those donations,” says Maine State Representative Diane Russell, D-Portland. “We all have the right to donate to political campaigns, and the responsibility to own up to those donations. It’s part of the democratic process.”

Russell has launched a national petition drive demanding that Romney come clean about the Barclays ties and the London fundraising event.

The “Mitt Romney: Reveal Your Secret Donors” petition reads:

It’s time we return to government of, by and for the people—not government of, bought, and paid for by special interests. The job of a Wall Street banker is to get a good return on their investment, and unfortunately, they’ve taken those skills to Washington—and now the presidency.

Mitt Romney is attending an elite London fundraiser—$25,000 to $75,000 per plate—hosted by the CEOs at the center of the Libor scandal threatening our already fragile economy. Executives of at least three other banks under investigation are co-chairs of the fundraiser, according to invitations obtained by The Washington Post.

At the same time, too many Americans are falling out of the middle class when they are working hard to climb the ladder into it. In fact, middle-class workers have seen their incomes drop by nearly 8 percent in three years and their wealth disappear by a staggering 40%.

We believe politicians should work for us, not their corporate sponsors. It is time for Mitt Romney to fully disclose his donors—and how much they are giving to his campaign.

Russell set out to collect 10,000 signatures.

She’ll get them. And a lot more.

Mitt Romney’s connection to Barclays and the Libor scandal is a big deal. Americans have a right to be angry that a man who wants to be president of the United States jets off to London to collect checks from international banksters. And the more they learn about Romney, Barclays and Libor, the angrier they’ll get.