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 center 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 that 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.

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In a now-deleted post on networking site LinkedIn, the Labour Party’s head of operations 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.”

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

According to the Federal Electoral Commission, which forbids any financial contributions, donations and expenditure from foreign nationals in any elections.

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 Donald Trump victory, Ms 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.”

Labour staff have travelled to the US during previous presidential elections to campaign for the Democratic nominee.

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

As recently as last month, Keir Starmer’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.

Last month, the prime minister met with Mr Trump in New York, the first face-to-face meeting between the pair.