Coach Mark Robinson has launched a staunch defence of Sussex wicketkeeper Matt Prior.

Prior came under attack from Kevin Pietersen yesterday with his former England team-mate accusing him of being a “schoolyard bully” who was a “negative influence” on the dressing room.

Robinson knows Prior as well as anyone having been his room-mate on away trips when the wicketkeeper first broke into the Sussex team in 2001 before going on to become his county coach.

He admits Prior’s burning desire to win can make him “headstrong” at times and that he sets high standards which he expects others to meet but has rejected Pietersen’s character assassination.

Robinson said: “I’ve not read what has been said and it is unfair for me to comment on the specifics as I’m not involved in the England dressing room.

“But all I can say is that from speaking to Andy (Flower, former England coach) and Pete (Moores, England coach and former Sussex coach) is that they speak very highly of Matt.

“His role in the dressing room is as a driver of the winning culture and making sure standards stay high. He has a great desire to win and sometimes that can come out not quite the right way but he is not a bully.

“From our point of view Matt has always been great. Obviously he has been with England for 90% of the time over the last five or six years but when we had him with us for an extended period of time from January he was brilliant.

“He is also a very loyal person. He stuck his neck out and gave the captain (Alistair Cook) a huge amount of support when he was coming under pressure. That is a quality you want to endorse and applaud rather than the opposite.”

Prior was responsible for ‘reintegrating’ Pietersen into the England set-up after he was dropped for sending derogatory text messages to the South Africa team about captain Andrew Strauss in 2012.

Pietersen claims their friendship soured when Prior was made vice-captain for the historic series victory in India in 2012 and then again during the tour of New Zealand last year.

Pietersen said: “Prior shouldn't be in that side because he's a bad influence, a negative influence - he picks on players. He's back-stabbing, he's horrendous, he's bad for the environment.”

Prior has called the accusations “sad” and says he will respond in the future but another former England team-mate Graeme Swann jumped to the Sussex star’s defence yesterday by dismissing Pietersen’s claims as a “work of fiction”.

Swann said: “I immediately realised it was codswallop when I read the character assassination of Matt Prior. Tragically I don’t think Kev realises the one person who fought tooth and nail to keep him in the side is the one person he is now assassinating: Matt Prior.”