After World War I, it was considered unlikely that large naval vessels would penetrate the inner archipelago. Instead, fixed barriers were to be established at the most important entry points to the Stockholm archipelago. The Navy requested the development of permanent coastal artillery further out in the archipelago to provide protection within the archipelago barrier. The so-called Havsbandslinjen - a defense line in the Stockholm archipelago - was created between 1933 and 1945, replacing the outer fortification line of Vaxholm. The artillery batteries of the line extended from Singö in the north to Landsort in the south. The 15.2 cm battery at Landsort (Battery LO) was the first to begin construction.
Batteri Utö 1 (UT 1) was established in 1940 on the northern tip of Utö (Stångudden) with the task of, together with Battery LB 2, preventing intrusions through Järnholmssund towards Mysingen and defending the controllable minefield LB 2 and the maritime barrier in the strait. The battery consisted of two 57mm cannons M/95 B in open emplacements, a command post, and an ammunition storage. The mine control station was located adjacent to the battery. The battery had a 150 cm searchlight.
All of these batteries were decommissioned during the 1960s and were subsequently replaced by the ERSTA system, which was taken out of service in the year 2000.
