If you are living in London, then taking a taxi can be the fastest and most convenient way of traveling from a station to your London apartment, or for taking you home safely at night. If you share a cab with other people, it is not always more expensive than other types of public transport.
A licensed taxi, which is regulated by the local government, can be found at a taxi rank or can be hailed while on the road by raising your hand towards the driver. The taxi is not authorized to stop when carrying other passengers or in an unsafe position. They are also not allowed to stop on roads with red lines painted on the edge.