This was a British deception by Colonel Dudley W. Clarke’s 'A' Force deception organisation to persuade the Axis powers that the Strait of Hormuz, between Iran and the Arabian peninsula and essential for the continued flow of oil for British use, had been mined (January/August 1943).
Together with 'Bijou' and 'Wyandotte', 'Workhouse' was proposed in December 1942 by Admiral Sir James Somerville, commander-in-chief of the Eastern Fleet, during a visit to Cairo. The object of 'Workhouse' was to protect Persian Gulf maritime traffic against the possible depredations by Axis submarines by persuading German and Japan that the Strait of Hormuz had been mined. The first concept was to sow this chokepoint dummy mines and provide an element of verisimilitude by actually blowing up some expendable craft. Then it came to be appreciated that the coast on each side of the strait was so thinly populated that no one was likely to note the fact, and that local fishermen would probably freely sail through the notional minefield. The submarine threat faded, and nothing much ever came of 'Workhouse'.
Later in 1943, responsibility for the area was switched to Peter Fleming’s 'D' Division, and on one occasion word that the strait had been mined was passed through one of the 'special means' (double agent) channels in Turkey at Fleming’s request.