Mr Romney added a further $2 million to his coffers at a $75,000-a-head dinner for affluent US expatriates, held at the Mandarin Oriental Hotel on Thursday.
But the funds raised in Britain are nothing compared with contribution from donors like Sheldon Adelson, one of the 10 richest Americans, who are willing to write $10 million cheques as down payments for the cause.
The Las Vegas casino magnate will be among the welcoming party of wealthy Jewish-American supporters of Mr Romney during his visit to Israel in Jerusalem this weekend.
Meetings with Israeli prime minister Benjamin Netanyahu, an old Romney managing consulting acquaintance from Boston, and Palestinian leaders were top of the official agenda for the former Massachusetts governor.
But in a fundraising event at the King David Hotel, Mr Adelson will be the star turn. The stridently Zionist billionaire and his Israeli wife Miriam have pledged to donate $100 million to Republican groups to fight November's elections, and gave $10 million last month alone.
Money and politics have long been inextricably linked in America, but the role of deep-pocketed donors has never been more prominent. And in a major reversal for President Barack Obama, who was the fund-raising behemoth of the 2008 campaign, Mr Romney is making the financial headlines this year.
The Adelsons, who at first backed his Republican primary campaign foe Newt Gingrich, are not even the biggest conservative contributors. The top spot goes to brothers David and Charles Koch, long-time supporters of libertarian causes, who have said that they will this year pour $400 million into groups that support Mr Romney and Republican candidates in national and state elections.
Most money goes to what are known in American campaign law parlance as "super PACs" (political action committees) - groups nominally independent of any candidate which can solicit and spend unlimited sums from individual donors, as well as from corporations and unions, on highly partisan advertising.
In this record-breaking year, the biggest financial juggernaut is American Crossroads, a super PAC headed by Karl Rove, the former chief political adviser to President George W Bush. The groupset a fund-raising target for this election cycle of $300 million, and is on course to beat that, while an affiliated "social welfare" pressure group is aiming to bring in another $100 million.
That means that Mr Rove -- once dubbed "Bush's brain" -- and his team will have more money with which to wage war on the airwaves in about 10 swing states than John McCain spent in total when he ran for president on the Republican ticket in 2008.
In the absence of individual donors on this scale, Mr Obama has been investing much of his time in lucrative fund-raising dinners hosted by the likes of George Clooney, the actor, in Los Angeles and Anna Wintour, the editor of Vogue, with the actress Sarah-Jessica Parker in New York.
Even before the final stages of the battle for the White House, the outlandish sums already raised and spent are head-spinning.
The Obama and Romney campaigns, combined with the two national parties, brought in more than $1 billion in total by the end of last month. In June alone, the Romney operation raised more than $100 million, leading Mr Obama to warn supporters that without more help he could be the first sitting president to be financially outpaced by a challenger.
Mr Obama is now effectively splitting his time between three jobs - governing, campaigning and fundraising - a division of duties that, say his critics, is contributing to political paralysis in Washington.
This year's figures are startling. Just 65 individual donors -- or the top one per cent of contributors to Super PACs -- have written cheques for more than $143 million so far, according to the Centre for Responsive Politics (CPR), which monitors campaign finances.
Those predominantly billionaire donors have been giving overwhelmingly to Republican-supporting groups, by a ratio of four to one. Some Left-leaning bastions such as Hollywood are simply disappointed with Mr Obama's performance, and the president is now at odds with many of his financial industry backers from 2008.
After nearly four years in office Mr Obama is finding his own supporters have lost much of their early enthusiasm, compared with his foes' ardour to oust him from the White House.
"For donors to want to give to a group like ours, two factors need to be in play," Jonathan Collegio of American Crossroads told The Sunday Telegraph. "They need to have a deep sense of concern about the direction of the country. And they have to sense the opportunity to change the direction of the country by helping the cause. We are seeing both these factors now."
The role of billionaire conservative donors in the campaign has prompted charges by liberal groups that they are "buying the election".
"You've got a few very wealthy people lining up trying to purchase the White House for Mr Romney," said David Plouffe, a senior Obama adviser, last month.
"Money matters in politics. We're running a great campaign, we've got millions of volunteers... but you've got to have enough money to run a one-year campaign. Our big concern are these super-PACs."
Mr Obama himself claimed in 2010 that such groups were a "threat to our democracy". Yet within months, his own supporters set up their own pro-Obana Super PAC run by Bill Burton, a former spokesman for the president.
Mr Collegio rejects the criticisms. "This is a classic case of double standards," he said. "Liberal groups and donors were ahead of the conservatives on this and in 2004 and 2008 they were running exactly the same type of ads that Crossroads is now."
The Supreme Court has ruled that the right to make unlimited donations is protected by the constitution. And as Mr Romney's overseas tour illustrates, the all-American amalgam of money and politics does not stop at America's borders.
But the funds raised in Britain are nothing compared with contribution from donors like Sheldon Adelson, one of the 10 richest Americans, who are willing to write $10 million cheques as down payments for the cause.
The Las Vegas casino magnate will be among the welcoming party of wealthy Jewish-American supporters of Mr Romney during his visit to Israel in Jerusalem this weekend.
Meetings with Israeli prime minister Benjamin Netanyahu, an old Romney managing consulting acquaintance from Boston, and Palestinian leaders were top of the official agenda for the former Massachusetts governor.
But in a fundraising event at the King David Hotel, Mr Adelson will be the star turn. The stridently Zionist billionaire and his Israeli wife Miriam have pledged to donate $100 million to Republican groups to fight November's elections, and gave $10 million last month alone.
Money and politics have long been inextricably linked in America, but the role of deep-pocketed donors has never been more prominent. And in a major reversal for President Barack Obama, who was the fund-raising behemoth of the 2008 campaign, Mr Romney is making the financial headlines this year.
The Adelsons, who at first backed his Republican primary campaign foe Newt Gingrich, are not even the biggest conservative contributors. The top spot goes to brothers David and Charles Koch, long-time supporters of libertarian causes, who have said that they will this year pour $400 million into groups that support Mr Romney and Republican candidates in national and state elections.
Most money goes to what are known in American campaign law parlance as "super PACs" (political action committees) - groups nominally independent of any candidate which can solicit and spend unlimited sums from individual donors, as well as from corporations and unions, on highly partisan advertising.
In this record-breaking year, the biggest financial juggernaut is American Crossroads, a super PAC headed by Karl Rove, the former chief political adviser to President George W Bush. The groupset a fund-raising target for this election cycle of $300 million, and is on course to beat that, while an affiliated "social welfare" pressure group is aiming to bring in another $100 million.
That means that Mr Rove -- once dubbed "Bush's brain" -- and his team will have more money with which to wage war on the airwaves in about 10 swing states than John McCain spent in total when he ran for president on the Republican ticket in 2008.
In the absence of individual donors on this scale, Mr Obama has been investing much of his time in lucrative fund-raising dinners hosted by the likes of George Clooney, the actor, in Los Angeles and Anna Wintour, the editor of Vogue, with the actress Sarah-Jessica Parker in New York.
Even before the final stages of the battle for the White House, the outlandish sums already raised and spent are head-spinning.
The Obama and Romney campaigns, combined with the two national parties, brought in more than $1 billion in total by the end of last month. In June alone, the Romney operation raised more than $100 million, leading Mr Obama to warn supporters that without more help he could be the first sitting president to be financially outpaced by a challenger.
Mr Obama is now effectively splitting his time between three jobs - governing, campaigning and fundraising - a division of duties that, say his critics, is contributing to political paralysis in Washington.
This year's figures are startling. Just 65 individual donors -- or the top one per cent of contributors to Super PACs -- have written cheques for more than $143 million so far, according to the Centre for Responsive Politics (CPR), which monitors campaign finances.
Those predominantly billionaire donors have been giving overwhelmingly to Republican-supporting groups, by a ratio of four to one. Some Left-leaning bastions such as Hollywood are simply disappointed with Mr Obama's performance, and the president is now at odds with many of his financial industry backers from 2008.
After nearly four years in office Mr Obama is finding his own supporters have lost much of their early enthusiasm, compared with his foes' ardour to oust him from the White House.
"For donors to want to give to a group like ours, two factors need to be in play," Jonathan Collegio of American Crossroads told The Sunday Telegraph. "They need to have a deep sense of concern about the direction of the country. And they have to sense the opportunity to change the direction of the country by helping the cause. We are seeing both these factors now."
The role of billionaire conservative donors in the campaign has prompted charges by liberal groups that they are "buying the election".
"You've got a few very wealthy people lining up trying to purchase the White House for Mr Romney," said David Plouffe, a senior Obama adviser, last month.
"Money matters in politics. We're running a great campaign, we've got millions of volunteers... but you've got to have enough money to run a one-year campaign. Our big concern are these super-PACs."
Mr Obama himself claimed in 2010 that such groups were a "threat to our democracy". Yet within months, his own supporters set up their own pro-Obana Super PAC run by Bill Burton, a former spokesman for the president.
Mr Collegio rejects the criticisms. "This is a classic case of double standards," he said. "Liberal groups and donors were ahead of the conservatives on this and in 2004 and 2008 they were running exactly the same type of ads that Crossroads is now."
The Supreme Court has ruled that the right to make unlimited donations is protected by the constitution. And as Mr Romney's overseas tour illustrates, the all-American amalgam of money and politics does not stop at America's borders.