The Press Association news service quoted police as saying that Campbell was taken to a central London station Wednesday for questioning after the assault allegation. Broadcaster Sky News carried a similar report. The Press Association said that Campbell was released later on bail.
A police spokesman refused to confirm the report, telling The Associated Press only that a 36-year-old woman had been detained Wednesday afternoon after an allegation of assault. The force has a policy of not naming people detained unless they have been charged with a crime, the spokesman said on condition of anonymity, in line with department policy.
The Press Association quoted a spokesman for the 36-year-old Campbell as saying he believed the incident was a misunderstanding that would be quickly resolved. The agency did not further identify the spokesman.
British media reported that the woman making the accusation was Campbell's drug counselor, who had gone to the police station to report the alleged assault.
According to the reports, police then went to Campbell's residence in London and took her into custody.
A New York-based defense attorney for the model, David Breitbart, said he had not spoken with Campbell and couldn't confirm the story. Campbell's representatives in London did not answer the telephone Wednesday night.
Campbell has faced legal problems before. The London-born model appeared in a New York court earlier this year to face allegations that she threw a phone at a maid. She also faced an allegation in 2003 and again in 2004 of assaulting people who worked for her.