HMS P556 (pennant number P556), was a S1-class submarine of the British Royal Navy.

She arrived at Gibraltar, via Bermuda, in August 1942 to refit, nominally as part of the 8th Flotilla.

Due to the number of mechanical failures it suffered, it acquired the nickname "Reluctant Dragon".

[1] HMS P556 was damaged by a battery explosion on 27 January 1944, and was decommissioned into the reserve in April.

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