"Do not lie to me! I can always tell, Wormtail! You are regretting that you ever returned to me. I revolt you. I see you flinch when you look at me, feel you shudder when you touch me..."
-- Voldemort, in his grotesque baby form (GF1)
Voldemort is in the form of a grotesque homonculus, kept alive with constant feedings of a potion which included venom from Nagini. Peter Pettigrew, now known only as Wormtail, is taking care of his master, although his distaste for the task is evident. Voldemort’s intention is to stay until the Quidditch World Cup is over:
“My Lord, may I ask how long we are going to stay here?”
“A week,” said the cold voice. “Perhaps longer. The place is moderately comfortable, and the plan cannot proceed yet. It would be foolish to act before the Quidditch World Cup is over.”
“The — the Quidditch World Cup, My Lord?” said Wormtail. “Forgive me, but — I do not understand — why should we wait until the World Cup is over?”
“Because, fool, at this very moment wizards are pouring into the country from all over the world, and every meddler from the Ministry of Magic will be on duty, on the watch for signs of unusual activity, checking and double-checking identities. They will be obsessed with security, lest the Muggles notice anything. So we wait.” (GF1)