She had a mundane career in the Royal Navy escorting convoys until in 1812, shortly after the outbreak of the War of 1812, she had the misfortune to encounter the frigate USS Essex, which captured Alert.

The next month Commander James Johnstone replaced Mackay and sailed Alert for the North Seas and the Downs.

Laugharne and Alert were cruising from Newfoundland searching for the American sloop USS Hornet when on 13 August they sighted a vessel at 41°0′N 32°24′W / 41.000°N 32.400°W / 41.000; -32.400.

Alert opened fire, but realizing that the American vessel was a frigate then sought to disengage.

He argued that allowing ships dispatched at sea to be considered cartels would be tantamount to granting all prizes immunity from recapture and would give them ultimate safe conduct to a port friendly to the captor.

[3] Captain Laugharne and a small crew embarked some 200 American prisoners of war and sailed for New York where she delivered them safely in the early autumn.

Alert was condemned by the New York Admiralty Court and sold to the United States Navy.

[5] The court martial board acquitted the remaining officers and men but expressed its disapprobation because they had all gone aft to plead with Laugharne to strike.