Aitor Karanka, the Middlesbrough manager, has followed up an attack on supporters by apparently picking a row with the club’s board after suggesting he has been let down in the transfer market.

Karanka appears to be close to breaking point as the pressure of a Premier League relegation battle takes its toll on the increasingly volatile Spaniard.

Although Boro chairman Steve Gibson is widely regarded as one of the best and most supportive chairman in English football, Karanka could be on a collision course with Middlesbrough’s benefactor after he suggested he will take the blame for other people’s failures.

Middlesbrough have signed two new strikers this month in Rudy Gestede and Patrick Bamford at a combined cost of around £12 million, to take the number of signings since promotion to 14, but Karanka feels more are needed and lashed out at those above him.

Middlesbrough have failed with attempts to bring in Bojan from Stoke and Robert Snodgrass from Hull this month. A move for PSG’s Jesé Rodríguez is also unlikely to be successful.