You would need to apply for a UK visitor visa. To enter England, Northern Ireland, Scotland or Wales (which make up the United Kingdom), you would require a UK visitor visa before leaving South Africa.

Your visa will normally be valid for up to 6 months. This allows you multiple entries into the UK during this period.

You may however apply for visas that carry a longer validity period. The validity periods range for up to 2 years, up to 5 years and up to 10 years but you may only stay for a maximum of 6 months per 12 month cycle.

The longer the validity of your UK visitor visa, the higher the UK consular fee will be.

Yes, all visa applicants would need to go in person when submitting their UK visa application as their finger prints and photos (i.e. biometrics) would need to be taken during their visa submission appointment. Children of all ages would also need to appear in person at their appointment.

According to the UK Border Agency itself, these are the rules. South Africa is part of the Direct Airside Transit Visa (DATV) agreement:

If you are a national of a country covered by the DATV system, you may be able to transit the UK airside without a visa. To qualify for this exemption;

• you must arrive and depart by air; and
• your onward flight must be confirmed, and must depart within 24 hours; and
• you have proper documentation for your destination, including a visa if necessary.

Additionally, you must hold;

• a valid entry visa for Australia, Canada, New Zealand or the USA, and a valid airline ticket for travel via the UK, as part of a journey to or from one of those countries; or
• a valid airline ticket for travel via the UK as part of a journey from Australia, Canada, New Zealand or the USA, if you are transiting the UK no more than 6 months after the date when you last entered Australia, Canada, New Zealand or the USA with a valid entry visa for that country