Blacks Leisure has confirmed it received a letter from Sports Direct last week indicating that it would consider upping its offer for the outdoor chain.

Sports Direct made an indicative offer of 62p per share for Blacks which the outdoor group rebuffed as “wholly inadequate. Sports Direct has been given till Thursday by the Takeover Panel to “put up or shut up” over its interest in Blacks.

There has also been more mud slinging between the two retailers; Sports Direct has made an allegation to the Takeover Panel that Blacks has been “selectively disclosing information about suppliers who were unlikely to continue to supply the group in the event of a successful bid by Sports Direct”.

It threatened to report Blacks to the Takeover Panel if it did not supply it with information on the suppliers who would not support the group if it makes a successful bid.

Blacks said: “Having reviewed this letter with its advisers, the board of Blacks, confident that there had been no selective disclosure in breach of the Takeover Code as alleged by Sports Direct, immediately referred the letter to the Takeover Panel.”

It added that it would continue to push ahead with its fundraising plans that have been blocked by Sports Direct.

Sports Direct said that it was continuing to “evaluate its position”.