Tottenham have given Chelsea until 1200 BST on Friday to resolve the row surrounding the Premier League champions’ approach to sporting director Frank Arnesen.
Photographs in Thursday’s papers show Arnesen on board Chelsea owner Roman Abramovich’s yacht but the club say the meeting was “purely a social occasion”.
“Having seen the pictures we’ve contacted Chelsea and set them a deadline,” said a Spurs spokeswoman.
“If we don’t reach agreement by noon on Friday, we’ll make a formal complaint.”
Spurs suspended Arnesen on 4 June after claiming Chelsea approached him without consent.
Chelsea, though, deny any wrongdoing, claiming they followed Premier League rules.
The club already have a suspended three-point deduction hanging over them after being found guilty of “tapping-up” Arsenal’s Ashley Cole. It has been suggested that Spurs are attempting to extract additional compensation out of Chelsea, in exchange for not reporting the incident to the Premier League.
The two clubs had been negotiating a compensation package when it became obvious Arnesen was keen to move to Stamford Bridge. However, the photographs from Abramovich’s yacht, have angered Spurs and resulted in Friday’s ultimatum.