The Daily Mail newspaper has apologised to the Joseph Rowntree Charitable Trust for calling it a "pro-terrorist charity".
The grant-making charity was criticised in a Mail story on 27 May for funding the company Operation Black Vote, which produced a controversial advert in the run-up to the EU referendum.
The advert, which depicted a white, male skinhead apparently shouting at an elderly Asian woman about Europe, was designed to show that votes carry equal weight whether they are cast by more or less vocal people, according to OBV.
It prompted more than 100 complaints to the Advertising Standards Authority within 24 hours of its launch.
The JRCT, which made two grants to OBV totalling £207,000, said at the time that it was committed to equality and that OBV had a strong track record of encouraging voter registration, democratic participation and debate.
A correction in yesterday’s Daily Mail said: "The first edition headline on an article on 27 May about the funding of the organisation responsible for a controversial referendum advert referred to the Joseph Rowntree Charitable Trust as a 'pro-terrorist charity'."
The paper said it was happy to clarify that the JRCT did not support or fund terrorism and apologised for the error.
"We are also happy to clarify that, while the JRCT is one of two organisations providing core funding to Operation Black Vote, it had no prior knowledge of the advert and did not pay for it."
The Charity Commission said in May that it had contacted OBV to ask why the organisation had described itself as a charity in its financial report when it was not registered with the regulator.
A spokeswoman for the regulator said today: "After we contacted Operation Black Vote to seek clarification on why it had described itself as a charity, we received a quick response to explain that this was an oversight and it would be contacting Companies House as soon as possible to rectify the error."
A spokesman for the JRCT declined to comment on the Daily Mail apology.