Sunderland approved the signage for a Newcastle-themed decoration of a bar at the Stadium of Light for Saturday’s FA Cup derby last month.

The PA news agency understands the Magpies were invited to submit designs for the Black Cats Bar, which will provide corporate hospitality for travelling fans for the third-round tie, in December and that they were signed off by a senior member of staff at the Wearside club.

It is understood the move was intended to lessen the potential for the area, which normally carries Sunderland’s livery, to be damaged by rival supporters.

Black Cats fans reacted furiously on Thursday when images of banners proclaiming the messages “Keep the Black and White Flying High” and “We are United” emerged on social media. Sunderland’s motto “Ha’way the lads” in red had also been replaced with the Geordie spelling “Howay” in black.

Sunderland swiftly apologised for “a serious error in judgment” and announced an immediate review, and chairman Kyril Louis-Dreyfus said he was “disgusted and hurt” by the “inappropriate signs”, which have since been removed.

There was already disquiet on the banks of the Wear after the hosts confirmed that Newcastle’s 6,000 allocation would be housed in both tiers of the North Stand, meaning some season ticket holders would have to relocate.

The controversy has added fresh spice to a fixture which is one of the stand-out ties of the round, although Magpies boss Eddie Howe played down suggestions that his club’s fans had been handed a head-start.

Howe said: “No, I don’t feel that. Look, these things can happen, it’s up to Sunderland what they do with their stadium. It’s nothing to do with us.”

The game, the first between the sides for almost eight years, represents Howe’s first taste of the Tyne-Wear rivalry, and he is expecting his players to handle the white-hot atmosphere.

Asked if he thought the signage row could further fuel the passion of the home fans, he said: “Regardless of what you’re expecting, you still have to play the match in front of you.

“We’ve just got to blank out any distractions and play the game and use our support – which I’m sure will be incredible – to propel us to a really good performance.”

Howe’s comments came after Louis-Dreyfus had issued a heartfelt apology to Sunderland fans and promised the club would do better in future.

He wrote on Instagram: “I would like to apologise to everyone associated with Sunderland AFC for the events that have unfolded today.

“Like our supporters, I was disgusted and hurt by the pictures circulating online of the inappropriate signs that have been ripped down.

“I take full responsibility for every decision that is taken by the employees of our club and you have my word that I will personally make sure that we make the necessary changes required to improve because it is clear that there are many areas where we need to be better.”