The Scottish side had hoped they'd be able to keep the 16-year-old, especially as they promised him a quicker route to first-team football, but he has rejected a three-year contract and now looks set to move to England.
Campbell joined the club in December 2018 and is regarded as one of the most exceptional young talents in Scotland.
Though he is yet to make his professional debut for the Scottish club, he has impressed for their youth teams, making his first Under-18s appearance at the age of 14. Liverpool plan to involve him in their Under-18s set-up initially before allowing him to graduate through the ranks.
Football Insider claim Campbell will visit Liverpool to have a tour of the club's stadium and explore their training facilities before sitting down with the club's representatives to discuss a possible move.
Liverpool are one of four Premier League clubs battling to sign Campbell, and PA understand Leeds and Brighton have also had bids accepted by Motherwell. Crystal Palace are monitoring Campbell's situation but haven't agreed a deal with the Fir Park club just yet.
Motherwell have granted Campbell permission to travel south of the border and hold talks with all of his potential suitors. He has agreed to visit Leeds' training ground over the next fortnight and the Yorkshire club are hopeful they can convince him to sign for them over their competition.