Newcastle United supporters have announced plans to step up their opposition to Mike Ashley's tenure at St James' Park in spite of the owner's attempts to sell the club. A newly formed fans group will broaden its boycott of official Newcastle goods and is to write to sponsors and advertisers requesting that they end their relationship with Ashley's regime.

Joe Kinnear, the interim manager, said yesterday that the billionaire had informed him that all bids to buy Newcastle “have to be in by October 17. He said six consortiums are interested.” While that timeline is unconfirmed, Newcastle are unlikely to be sold until mid-November at the earliest.

The likelihood of Kinnear remaining far beyond the end of his contract, which runs until the end of this month before becoming a “rolling” deal, is strong, but Tynesiders would be less enamoured by Ashley's continued presence. The latest statement from the Newcastle United Supporters Club (NUSC) warned against complacency.

“NUSC would be delighted to discuss with any prospective buyer of good intention how we can work together,” the organisation said. “Mike Ashley is not acting quickly enough to end his disastrous relationship with our club. NUSC will soon be writing to the club's main sponsors and advertisers to request that they end their business relationship with a Mike Ashley-owned Newcastle United.

“If the nightmare scenario of an Ashley-owned Newcastle United continues to next summer, then we will organise a campaign amongst supporters to boycott any new kit and merchandise being sold by adidas.”

There has been a further intervention from Freddy Shepherd, the club's former chairman. “No one's going to give Mike Ashley a huge profit for the club now,” he said yesterday. “Whoever's going to buy it will know they have to buy players. If Ashley doesn't sell the club by January, he's going to have to strengthen the team. That's why he will be aiming to sell the club before the transfer window opens.”