There occasionally comes a time when you have to lay down a marker. Saints did just that yesterday.

Their decision to ask the Premier League to investigate an alleged illegal approach by Liverpool for Virgil van Dijk was the very clear drawing of a line in the sand.

It was an unexpected move, but a decisive one.

The anger at St Mary’s was bubbling up on Monday afternoon as a raft of stories from journalists with strong connections to Liverpool all appeared at around the same time saying van Dijk wanted to move to Anfield.

There was no source attributed, and Liverpool officially refused to comment in the reports.

However the stories came to pass, there is nothing illegal in it. This sort of thing happens all the time in football.

What really got Saints was that some reports suggested van Dijk was sold on the move due to, as one put it, Jurgen ‘Klopp’s personal involvement in Liverpool’s effort to sign him.’ This really muddied the waters, and strayed beyond what Saints felt was just part of the game that football clubs play in the transfer market.

We don’t know if we are dealing with cases of journalistic licence or if the reports are correct, but no club can directly speak to a player until they have permission from the club he is contracted to, and Saints have had no bid from Liverpool for van Dijk. Any approach to the player would, therefore, be considered illegal under current rules.

The furious Saints hierarchy met yesterday morning to discuss their response, and decided to ask the Premier League to investigate. It is now for them to establish whether has been any wrongdoing or not.

For Saints this move has two positive effects.

It is a chance to do what they think is right, and to back up their actions with words.

They are utterly determined that they won’t be bullied in the transfer market any more by clubs who want their players.

While even the biggest clubs in the world do sell top players, Saints want to dictate the terms of play and not just be trampled over with the vultures picking off who they like, however they like.

Chairman Ralph Krueger made it quite clear just a few weeks ago that for the first time in several years Saints do not feel the need to sell to fund new faces to bulk up the depth of the squad. Gone are the days of selling two players for high fees to bring in five new faces.

And with van Dijk having five years left on his contract, Saints have been much more relaxed about the situation than in previous summers.

They want more out of him. At least another year.

Their calculation remains that, barring some catastrophic injury, his value will be at least as high next summer, and there is no doubting another year of van Dijk at St Mary’s would be a huge boost for the club.

The only way in their eyes that van Dijk leaves is if a club is prepared to pay a significant premium on top of his current market value for the right to deny Saints having him longer.

When we talk numbers on this £60m will not do the job. And if Saints sold him for say £70m or more, most fans would surely recognise that is actually a good deal as that money would be reinvested in the squad.

What we don’t know is how van Dijk will react to all this. We don’t know his state of mind. We don’t know that he ever wanted to join Liverpool, if he wants to stay at Saints, or indeed go somewhere else.

It will be another big test if van Dijk insists the reports are true and he does want to move to Anfield. Saints then face a tough moment. They either have to negotiate, or tell him it’s not happening.

Van Dijk does not seem like the kind of guy who is going to kick-off over it all. He’s a nice and reasonable person. And Saints will no doubt point out one who just a year ago was happy to sign a six-year contract in return for the vast riches Saints were offering and have paid even though he missed the second half of the season through injury.

In these days of player power nothing is ever certain, and you feel the ball is very much in van Dijk’s court now, unless Liverpool, or Manchester City or Chelsea for that matter, break rank and start the bidding.

Saints have signalled they are prepared to play hard ball now. If they stick to their guns then we really will be seeing a change at the club.