Liverpool have abandoned their hopes of signing Virgil van Dijk and apologised to Southampton for "any misunderstanding" over their interest after they were accused of "tapping up" the player.
But what is "tapping up"? The most famous case in recent history was arguably Ashley Cole's move from Arsenal to Chelsea back in 2005 when the player, as well as Chelsea and their manager Jose Mourinho, were fined.
Via email, ESPN FC asked Ross Brown, senior associate at sports law practice Onside Sport, to explain what "tapping up" constitutes.
Q. What exactly is "tapping up"?