Southampton's Virgil van Dijk. Photo: Paul Childs/Reuters

LONDON - The Premier League will ask Liverpool for their observations after they were called upon by Southampton to investigate whether they had made an illegal approach for Virgil van Dijk.

Southampton are livid about Liverpool’s conduct in pursuing the Holland central defender and contacted the governing body yesterday to air their grievances.

Liverpool have made Van Dijk their top transfer target and are ready to smash the world record fee for a defender to bring him to Anfield. He is believed to want to work with Jurgen Klopp and that has prompted him to ignore the advances of Manchester City and Chelsea.

Liverpool have refused to comment but the Premier League confirmed they had been contacted by Southampton. A spokesman said: ‘Southampton have raised some concerns and we are in turn raising them with Liverpool.’

Premier League rules stipulate that a club can only approach a target if they have the written consent of the selling club or if the player is out of contract or his contract is about to expire.

There is no suggestion yet that Liverpool face any kind of censure and they have not made contact with Southampton in terms of lodging an official bid.

It emerged on Monday, however, that Van Dijk wants to join them and it prompted a furious reaction at St Mary’s as Southampton believe Liverpool have unsettled the 25-year-old.

The two clubs have done frequent business over the last three years, with Liverpool buying five players from Southampton for more than £90million. It is inevitable now, though, that negotiations will be strained. Southampton have insisted that Van Dijk is not for sale, even though his future has been the subject of intense speculation.

City indicated they would not be prepared to pay more than £45m for Van Dijk, who has not played since January through injury, while Chelsea’s need to sign a central defender is not pressing.

Van Dijk has five years remaining on the six-year deal he signed 11 months ago and could be forced to stay, as was the case with Morgan Schneiderlin in 2014 when he was wanted by Arsenal and Manchester United. The reality, however, is that he has set his heart on playing for Liverpool but he will not be offered an easy route to Anfield.

Having valued Van Dijk at £50m, it is likely to take a figure closer to £60m to secure his release, particularly as his former club Celtic will get 10 per cent of the fee.