An individual is entitled to enter the United Kingdom as a visitor in transit if he/she is scheduled to arrive the UK, moves through the Immigration control and then vacate the UK within 48 hours of arrival or 24 hours in cases where the individual is travelling under the ‘travel without visa’ concession. This is termed the transiting landslide.
In a situation, where the individual arrives the UK on a flight, remains in the arrival lounge of the airport without moving through the immigration control and the leaves with another flight from the same airport, he/she is does not need to enter as a visitor in transit. This situation is known as the transiting airside.
However, for an individual to enter the United Kingdom as a Visitor in Transit, he/she must be able to exhibit that:
The individual is not permitted to take up employment during his/her stay in the UK. Visa Nationals are required to obtain a UK visa before they will be granted entry into the UK as a visitor in transit.
On the other hand, if an individual seeks to transit the UK whilst on his/her way to a country that is among the Common Travel Area (Ireland, the UK, the Isle of Man and the Channel Islands), the person would not be granted entry to the UK as a Visitor in transit.