Why did Bill Haydon insult Easterhase in this scene?

Question

After Jim was killed in a trap, Esterhase waves hands at people who had completed their meeting with Control. Then Bill insults him:

Bill Haydon: You little prick, Esterhase

Why does he say that?

Answer 1

Control has just signed over leadership of the Circus and is being 'retired'. Smiley is his right hand man and is leaving with him. The four lieutenants, Haydon, Esterhase, Alleline and Bland will now be the leadership of the Circus. Esterhase was glad Control was leaving, and hastened the departure by opening the lift's gate. Everyone understood that Control had given a lifetime of work into the Circus and departing was very, very hard for him, yet there was the little toad Esterhase, smiling.

Bill Hayden was simply calling out Esterhase on his bad manners for gloating over Control's departure.

In the script, it is written:

INT. CIRCUS - FIFTH FLOOR - DAY 7

PUSHING Control and Smiley as they walk down the corridor. 5.

Alleline and the Lieutenants are waiting for them. A horribly awkward moment. Toby pulls open the cage lift doors for them, as if to hasten the eviction. Haydon looks at him with contempt.

BILL HAYDON

You little prick Esterhase.

Control sweeps past them and the lift, determined to walk every step of the way. Smiley follows.

In a wiki for the same scene, it is described in a way to maybe make it more understandable (although you really might have to read the novel for understanding it better):

Control: [Control has just signed an official document of the British Intelligence Service.] Would you witness this for me?
Percy Alleline: I wish I could've done more, Control.
Control: You did all you could, Percy. Well, a man should know when to leave the party.
Toby Esterhase: What about Smiley?
Control: Smiley is leaving with me. [Smiley nods to the affirmative.]
Bill Haydon: [having an inaudible conversation with Esterhase. Esterhase then waves mockingly at Control and Smiley, both of whom are leaving 'The Circus'.] You little prick, Esterhase!