SA nationals in transit from Canada to Jo'burg through LHR - landside visa required?

critical update this will not work for SA nationals, as of 2015. See info on the new rules here

https://www.gov.uk/government/publications/changes-to-transit-visas-immigration-act-2014/changes-to-transit-visas

The discussion here is basically about whether "Travel Without Visa" concession is applicable to South African citizens. The short answer is "in certain special cases".

Citizens of most countries only need to fulfill three simple requirements:

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

But if you are unlucky, and happen to hold a passport of one of DATv countries (e.g. South Africa), the rules are significantly stricter: in addition to the above conditions, you have to fulfill one of the requirements from the list Doc quoted in his answer. In the case of your friends, the following condition is met, they hold:

a valid visa for entry to Canada or the United States of America and a valid airline ticket for travel via the United Kingdom from the country in respect of which the visa was held to another country or territory

Some third-party websites also state that you must depart from the airport of your arrival, but this is nowhere mentioned on the UKBA website, so, probably, is outdated.

The only thing one should be afraid of, is to be denied boarding at the airport of departure in Canada (it is ridiculous to deport your friends from LHR to South Africa if they already have tickets for a flight going there in 9 hours). Now, during the check-in procedure at the airport of departure the airport staff will check whether you have all the required travel documents (visa, valid passport, etc.). For that purpose they will probably use Timatic, an automated system similar to http://www.iatatravelcentre.com/. Just type in all the travel details there, and see what the system says. If it says yes, you will be allowed boarding.

P.S. As MeNoTalk mentioned, there are indeed cases when it is safer to have a visa. Apart from saving time (it took me around 10-15 minutes to show all the necessary documents in order go through the passport control in LHR using the "Travel Without Visa" concession, but I am not a DATv national), it is recommended if

• you have any unspent criminal convictions in any country, including the UK;
• you have previously been refused entry, deported or otherwise removed from the UK;
• you have breached the terms of any previous entry to the UK (for example, by working illegally or staying here after your permission to stay expired);
• you have previously applied for a visa and been refused; or
• you have been warned by a UK official that you should obtain a visa before you travel to the UK.

Timatic, which is the immigration system used by most airlines globally, states the following for a South African citizen travelling to Canada via the UK.

United Kingdom (GB)

TWOV (Transit Without Visa): Visa required, except for Passengers who may be granted permission by the Immigration authorities to enter the United Kingdom, for a stay not exceeding 24 hours. The following conditions must be complied with:

• passengers hold confirmed reservations for an onward flight within 24 hours; and

• continue to a third country; and

• have no purpose in entering the United Kingdom other than to pass through in transit; and

• hold all documents required for the next destination.

  • Warning Nationals of South Africa may use this administrative concession (TWOV) above if holding:

  • a visa which allows entry into (or transit through) either Australia, Canada, New Zealand or the USA; and

  • holding a valid ticket for travel from a third country or territory via the UK as part of a journey TO (or through) Australia, Canada, New Zealand or the USA, whichever the visa is applicable to (e.g.: DEL-LHR-JFK, DEL-CDG-LHR-JFK, DEL-LHR-CDG-JFK or DEL-LHR-JFK-MEX). OR:
  • a valid visa for entry into Australia, Canada, New Zealand or the USA; and
  • a valid airline ticket for travel via the UK as part of a journey FROM the country in respect of which the visa is held to another country or territory. OR: travelling as part of a journey FROM either Australia, Canada, New Zealand or the USA, provided transiting the UK less than 6 months after the date they last entered Australia, Canada, New Zealand or the USA with a valid visa for the respective country, even though the visa may have expired at time of transit through the UK (e.g.: JFK-LHR-DEL, JFK-CDG-LHR-DEL or JFK-LHR-CDG-DEL). NOTE: this DATV exemption is not applicable if holding a US Visa Foil type "YY" or "ZZ" endorsed "Not a visa. Foil prepared at DHS request" nor the US Adit stamp worded "Processed for I-551" (temporary form I-551).

Presuming your friend holds a visa to enter Canada (which I would presume they do), then the above should apply to them. The only condition which is likely to cause an issue is "have no purpose in entering the United Kingdom other than to pass through in transit" - meeting you in itself could contract that condition.

The UK Home Office Website also confirms this under the "'Transit without visa' concession" section under More Information.