Coventry's request to play their 'home' fixtures at Sixfields for the next three seasons was reluctantly approved by the Football League earlier this week.
The Sky Blues announced plans to move into a new stadium in May, claiming they had been given no choice but to leave the Ricoh Arena due to a protracted and bitter rent row with stadium management company Arena Coventry Limited (ACL).
The groundshare has been met with anger from the vast majority of Coventry supporters, who must travel 34 miles across the M6 and down the M1 to watch 'home' games, while ACL had called on the Football League to block the proposal, insisting home fixtures should be played at the Ricoh Arena.
Despite the Football League's decision to back the move, it would appear ACL are not about to give up the fight.
A brief club statement on Northampton's official website read: "Northampton Town Football Club confirms that Arena Coventry Limited (ACL) has threatened the club with legal action in respect of Coventry City FC playing at Sixfields Stadium.
"The club was approached by Coventry City to play at Sixfields, so that Coventry City could fulfil its fixtures. The Football League has endorsed this arrangement.
"The threatened action by ACL is without any legal merit and is not conducive to the greater good of the game.
"Northampton Town Football Club will not be bullied or threatened."