What does the cryptic crossword clue "At length, Peter's prepared to tackle problem boldly (5,3,6)" mean?

The wordplay uses an anagram. anagram of AT + LENGTH, + PETER'S = GRASPTHENETTLE The answer is GRASPTHENETTLE.

At length, Peter's prepared to tackle problem boldly (5,3,6)

Daily Mail Cryptic #16728 | 1 Down | 2021-12-14 flower