Which transferred sloop remained in service the longest?

Which former Royal Navy sloop remained in service the longest?

Probably the vessel serving India as Krishna, which remained active until 1981; German transfers also served into the 1960s and 1970s.

Several Royal Navy sloops outlasted their British careers under foreign flags. Mermaid served West Germany as Scharnhorst until 1974, while Flamingo served there as Graf Spee before disposal in 1967. Another former sloop served the Indian Navy as Krishna until 1981, making the Indian transfer the likely last operational survivor discussed here. Operational service, final payoff, and later breakup are different measures, so the identification remains tentative.