Speaking at a Centaur retail distribution review conference this week, chief executive Richard Fox warned that lenders needed to give greater focus to customer retention.
He questioned whether tactics such as imposing admin fees were in line with TCF.
Fox said: “If you do not have lenders who step out of line, it is only a matter of time before consumer groups will turn round and say, is there collusion going on here?
“I do not know whether there is or not but it begins to look as if there might be. And if there is collusion, what about TCF? Where does that sit with it?”
Fox said lenders needed to look at changing the way brokers are remunerated to place a greater emphasis on fees.
He said this would improve their profitability without the “blatant widening of margins” that is taking place.