I've had a chat with a dealing desk broker and got to know this from the conversation
Broker: We are a dealing desk.
Me: does the dealing desk trade against customers?
Me: i've heard several rumours about dealing desk doing that
Me: such that they do not only earn from spread only
Broker: Dealing Desk firms do provide you constant liquidity all time instead of forwarding every order they receive to a bank.
Broker: This means that you get a better and faster execution.
Can anyone confirm this if it's true?