Thousands of southerners are fleeing northern Sudan, as tension grows in the build-up to January's referendum on independence for the south of the country.

The government of southern Sudan is organising many of the returns and paying for transport, although some people have been waiting for weeks to leave.

Many southerners are concerned that, if the south votes for independence, they would no longer be welcome in the north.

James Copnall went to meet some of the people planning to leave Khartoum.