pleased as punch

(as) pleased as punch {UK} (very happy) — очень рад, очень доволен; ≅ рад-радёшенек, от души рад; ≅ рад как не знаю кто

also spelt (as) pleased as Punch

Example 1: They are going to be as pleased as Punch. — Да они с ума от радости сойдут.

Example 2: When I heard our offer for the house had been accepted I was as pleased as punch.

Example 3: Your mother will be as pleased as punch when she finds out you are going home for Christmas. (ecenglish.com)

Example 4: "We teach them the three Rs. Well let's add two more — right and wrong." The slogan is so grey-haired that even at party conferences it wouldn't get a ripple of applause. He looks around for a moment, pleased as punch, then realizes that his fellow group members have all heard it a dozen times before. (Jeremy Paxman, Friends in high places: who runs Britain? )

Example 5: As we get into the car, he nags because I haven't put my seatbelt on. "You're extremely bossy," I tell him. "I am, rather, aren't I?" he says, pleased as Punch. (Daily Telegraph, elect. edn. of 19920411, Leisure material)

Related vocabulary
[in seventh heaven]
[on cloud nine]
[over the moon]
[on top of the world]
[jump for joy]
[thrilled to bits]

Punch’s name comes from Polchinello (sometimes spelled Punchinello), an Italian puppet with similar characteristics. In Punch and Judy shows, the grotesque Punch is portrayed as self-satisfied and pleased with his evil actions. (ecenglish.com)