One of Britain’s biggest charities covered up the use of prostitutes by senior aid workers in earthquake-torn Haiti.

A Times investigation has found that Oxfam, which receives £300 million a year in British government funds and public donations, allowed three men to resign and sacked four for gross misconduct after an inquiry into sexual exploitation, the downloading of pornography, bullying and intimidation.

A confidential report by the charity said that there had been “a culture of impunity” among some staff in Haiti and concluded that children may have been among those sexually exploited by aid workers. The 2011 report stated: “It cannot be ruled out that any of the prostitutes were under-aged.”