Liverpool will sign Virgil van Dijk from Southampton next week after agreeing a fee of £75m for the Holland international – a world record for a defender. The Merseyside club had wanted him to join last summer and indicated a willingness to pay £60m only for the move to break down in acrimonious fashion.

Southampton felt that Liverpool had overstepped the mark and tapped up Van Dijk – they made a formal complaint to the Premier League and Liverpool duly backed off, with the player’s other admirers, chief among them Manchester City and Chelsea, doing likewise.

Southampton felt compelled to make a stand over their star player as they began life under a new manager, Mauricio Pellegrino, and they hoped that Van Dijk would apply himself and recapture the form he had shown at St Mary’s since his £11.5m switch from Celtic in 2015 – if only for another season.

It has not worked out that way, however. Van Dijk has appeared to have done no more than go through the motions and Pellegrino has come to accept that his departure is inevitable. He has not played the defender in Southampton’s past three matches.

Negotiations between the two clubs accelerated over the festive period before Van Dijk underwent a medical on Wednesday after successfully agreeing personal terms on a contract until 2023 worth in the region of £180,000-a-week.

“Liverpool football club can confirm they have reached an agreement with Southampton for the transfer of Virgil van Dijk,” read an official statement. “The Reds have agreed a deal with the south coast club, and the player himself, that will see the 26-year-old defender move to Anfield when the transfer window re-opens on 1 January 2018.”

Quick Guide The world's most expensive defenders Show 1. Virgil van Dijk, Southampton to Liverpool, £75m The defender is set to move from the south coast in the 2018 January transfer window. 2. Kyle Walker, Tottenham to Manchester City, £54m The former Spurs wing back joined Manchester City in July 2017. 3. Benjamin Mendy, Monaco to Manchester City, £52m The former Monaco left-back was briefly the world's most expensive defender until Walker made his move. 4. David Luiz, Chelsea to PSG, £50m The Brazil international left Chelsea for PSG in June 2014 before moving back to London in August 2016. 5. John Stones, Everton to Manchester City, £47.5m The then 22-year-old defender was Pep Guardiola's eighth signing in August 2016. 6. Shkodran Mustafi, Valencia to Arsenal, £35m The German international signed for a fee of 'more than £35m' in August 2016. 7. David Luiz, PSG to Chelsea, £34m David Luiz made a surprise return to Chelsea, with the London club paying £16m less than they sold him for. 8. Thiago Silva, Milan to PSG, £33m Thiago SIlva's move in July 2014 made him the world's most expensive defender for a period. 9. Eliaquim Mangala, Porto to Manchester City, £32m The France international moved to Manchester in August 2014 but has not proved a success. 10. Nicolas Otamendi, Valencia to Manchester City, £31.5m The Argentina defender signed a five-year deal on his arrival from Valencia in August 2015. Photograph: Peter Dejong/AP

Southampton feel they have made their point over Van Dijk, even if they could no longer rely upon top-level performances from him. They have had no qualms about dealing with Liverpool – particularly as they have extracted a significantly higher fee from them. Their view is that January marks a fresh start and it is in their interests to take the money and move on.

Van Dijk released a statement on Twitter saying: “[I am] delighted and honoured to have agreed to become a Liverpool FC player. Today is a proud day for me and my family as I join one of the biggest clubs in world football. I can’t wait to pull on the famous red shirt for the first time in front of the Kop and will give everything I have to try and help this great club achieve something special in the years to come.

“I would also like to take this opportunity to say thank you to Les Reed, the board, manager, players, fans and everyone at Southampton. I will always be indebted to the club for giving me the opportunity to play in the Premier League and despite a difficult last few months I have thoroughly enjoyed my time at Saints and have made friends for life at the club. Thank you for everything.”

Van Dijk will wear the No4 shirt at Liverpool and may make his debut in the FA Cup third-round tie against Everton on 5 January. He is also eligible to play in the Champions League, in which Liverpool face Porto next. He has long had his heart set on the move to Anfield, together with the chance to work for Jürgen Klopp, and he is primed to follow a well-trodden path.

Liverpool had previously spent £96m on five Southampton players since the summer of 2014. In that transfer window they took Adam Lallana (£25m), Dejan Lovren (£20m) and Rickie Lambert (£4.5m). Nathaniel Clyne (£12.5m) and Sadio Mané (£34m) followed in the summers of 2015 and 2016 respectively.

Manchester City had made Van Dijk one of their principal targets and they were ready to bid £60m for him. But the situation has moved on quickly in recent days. City paid £54m to Tottenham Hotspur last summer for the right-back, Kyle Walker, which raised the bar in terms of fees for defenders. But Liverpool have raised it again for Van Dijk.

It is understood Southampton will earn around £70m up front with a further £5m of clauses and performance-related add-ons, while Celtic are expected to net around 10% of the fee as a result of the £11.5m deal that saw Van Dijk head to Southampton in 2015. Pellegrino will be allowed to reinvest a significant amount of the Van Dijk fee next month although Southampton are not expected to go on a spending spree when the window re-opens on January 1.