More than £1tn may have flowed out of Africa illegally over the last four decades, most of it to western financial institutions, according to a new report. Even using conservative estimates, the continent lost about $1.8tn (£1.18tn) – meaning Africans living at the end of 2008 had each been deprived of an average of $989 (£649) since 1970, according to the US-based research body Global Financial Integrity (GFI).