You can't fly direct from Manchester to South Africa, but with so many one-change routes available, that shouldn't put you off. The quickest way to Johannesburg is to catch either a Lufthansa, Swiss or Air France flight via mainland Europe, which should all take a shade over 13 hours.
Alternatively, if you are en-route to Cape Town, you could hop on a British Airways service that routes via Heathrow or an Air France flight via Paris. Either way, they should take about 14 hours. You can also travel to Durban with Emirates in between 18 and 19 hours, so there is plenty of choice on offer. To find the best flights for you, check out our flight search tool.
If changing planes sounds like too much hassle, you can fly direct from Heathrow to South Africa. British Airways fly direct to both Cape Town and Johannesburg in between 11 and 12 hours, while Virgin Atlantic and South African Airways also fly non-stop to Johannesburg.
If on the hunt for a bargain, avoid booking your flights for high-summer (November-February) or the European summer period between June and August, as this is when demand for flights is very high. The best time to take a holiday in South Africa is probably around March-April time, as the temperatures are still in the 20s, the rainy season hasn't taken hold yet and flights can be cheap. Just make sure you book well in advance to get the best deal.