Sidney Louis Walter Merlin (Greek: Σίδνεϋ Μέρλιν; April 26, 1856 – July 14, 1951) was a British botanist and sports shooter.

His family had lived in Greece since the 1830s, where his father, Charles William Louis Merlin, was British Consul at Piraeus.

They had a daughter, Adela Maria ( Maraki) Lappas, née Merlin, a novelist, WW2 war correspondent and potter.

He later divorced Zaira and married Kakia Inglessi, Greek by birth whose aristocratic family had lived in Russia before the revolution.

The mansion, known as Bella Capina (Pelakapina in some spellings) also provided a residence for King George II, and meeting rooms for the Greek War Cabinet and government for several months.

This is historically interesting, as it is one of the very few occasions when information from Bletchley Park, where German intelligence was decoded by the British, was given to non-British individuals.