England will replace the Proteas as the No 2-ranked Test side on the ICC rankings.
The rankings will be updated at the conclusion of the series between England and Sri Lanka in Colombo next week.
England’s 57-run victory in the second Test in Pallekele gave them an unassailable 2-0 lead, as well as second spot on the rankings, irrespective of the result in the third Test.
If England win the Colombo Test, they will finish on 108 points, two more than South Africa, while a Sri Lanka win will mean England will join South Africa on 106 points, but will be ranked a fraction of a point above the Proteas.
A drawn Test will mean England will finish on 107 points – nine points behind No 1-ranked India and one point ahead of South Africa.