"That's normal when players are unhappy with challenges. We have a go at each other and it goes on in every game."It's only words and nothing normally ever comes of situations like that, but the situation with Richie Wellens was a poor one from him. He spat in my face."The FA confirmed the alleged incident was not caught on camera or spotted by referee Scott Mathieson so the investigation will take longer than the FA's 48-hour 'Fasttrack' procedure.The FA's compliance unit will talk to both Britton and Wellens as well as seek the observations of the other players and members of the coaching staff that claim they witnessed the incident."No-one, including their manager, can say they saw me spit in his face," Wellens told Doncaster's official club website."Britton, though, added: "It wasn't a face-to-face spit. I was literally by the side of him and he spat out of the side of his mouth."Maybe he was trying to provoke a reaction... but you've got to rise above that."Swansea boss Roberto Martinez immediately called on The FA to take action over former Manchester United trainee Wellens."There was one incident which you don't want to see on football pitches," said Martinez. "That's unacceptable."You get sent off for football situations but when you step over the line, I think the authorities should look at that situation."Doncaster refused to put midfielder Wellens up for interview to respond to the allegations immediately after the game but boss Sean O'Driscoll said: "If you ask Richie, he will say he didn't do anything. "I didn't see anything. You've got their right-back almost throwing a punch at Richie. Does he have to be sent off? I don't know."It's something that hopefully won't make the headlines because Swansea deserved, on their performance, to win the game and they did it in the right way as well.Wellens was sent off in the 85th minute after receiving two yellow cards in incidents unrelated to Britton's allegation.