When Ted Turner pledged 11 years ago to give $1bn to the United Nations to cover the unpaid dues of the US, there was an unexpected hitch.

Under UN rules, the US could not abrogate its debt, and there was no mechanism for individuals to make donations to the UN. So Mr Turner, who had founded the cable television television channel CNN and sold it to Time Warner, created a foundation to make the donation. The idea was that the funds would be channelled into UN causes – poverty, maternal and child health, and protecting world heritage.