Donald Trump's campaign team has called for an investigation into what it claimed was "blatant foreign interference" in the election by the Labour Party.

The complaint to the US federal electoral commission claimed there had been "interference" in the "form of apparent illegal foreign national contributions made by the Labour Party of the UK" which had been "accepted" by Kamala Harris's campaign.

It references a Washington Post report that suggested "strategists linked to Britain's Labour Party have been offering advice to Kamala Harris about how to earn back disaffected voters and run a winning campaign from the centre left".

It also mentions a Telegraph report that suggested Morgan McSweeney, Sir Keir Starmer's chief of staff, and Matthew Doyle, his director of communications, "attended a convention in Chicago and met with Ms Harris's campaign team".

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There is no evidence the Labour Party had made any financial contributions to the Democrat campaign, something that is prohibited under US law.

But some of Mr Trump's allies have nevertheless taken issue with Labour Party staff volunteering on Ms Harris's campaign, even though this is permitted under US law as long as the said volunteers are not compensated for their work.

In a now-deleted post on networking site LinkedIn, the Labour Party's head of operations, Sofia Patel, said last week: "I have nearly 100 Labour Party staff, current and former, going to the US in the next few weeks, heading to North Carolina, Nevada, Pennsylvania and Virginia.

"I have 10 spots available for anyone available to head to the battleground state of [North] Carolina - we will sort your housing."

It is understood the trips are for individuals in a personal capacity, funded by themselves and in their own time - they are not organised or funded by the Labour Party.

The accommodation is also being arranged by volunteers campaigning for the Democrats.

The complaint, filed on behalf of Donald J Trump for President 2024, said that foreign nationals are prohibited from "directly or indirectly" making "a contribution or donation of money or other thing of value, or to make an express or implied promise to make a contribution or donation," in support of an American candidate.

US law forbids any financial contributions, donations and expenditure from foreign nationals in any elections.

They are also prohibited from participating in decisions involving election-related activities.

However, they are allowed to volunteer in campaigns "as long as the individual is not compensated by anyone for the services".

Last week a government minister told Sky News it was "normal" for Labour staff to campaign for a Democrat candidate.

Asked whether Labour staff helping with the Democrat campaign could damage the UK's relationship with the US in the event of a Mr Trump victory, Alison McGovern told Sky News: "As far as I know, this is a voluntary thing and it's about volunteers going and sharing their time.

"This is a normal thing that happens in elections."

This election is not the first time that both Labour and Tory staff have campaigned for the Democrats and Republicans, to whom they are closely linked.

David Axelrod, a former adviser to Barack Obama, helped Ed Miliband's campaign in 2015, while Jim Messina, another former Obama campaign aide, assisted David Cameron's campaign that same year.

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Senior Conservatives in the UK, notably former prime minister Liz Truss, have also attended high-profile Republican events, including the National Convention in July.

And as recently as last month, Sir Keir's former pollster, Deborah Mattinson, reportedly met Ms Harris's campaign team in Washington to share advice on the election following Labour's landslide victory in July.

The prime minister also held his first face-to-face meeting with Mr Trump in New York last month.

Sir Keir said ahead of the meeting that he was a "great believer in personal relations on the international stage".

"I think it really matters that you know who your counterpart is in any given country, and know them personally, get to know them face to face."

(c) Sky News 2024: Trump campaign files complaint over 'blatant foreign interference' by Labour Party in US elect