[11] In September 2023, the UK and the Netherlands signed a Memorandum of understanding announced to explore the joint procurement of amphibious warfare ships under Project CATHERINA.
[11] However, in March 2024, this main effort was reportedly abandoned as the two parties identified that their requirements and budgets were too divergent for a single design to successfully meet.
One key difference was the ships' ability to operate independently without an escort — a British preference which would require more substantial self-defence capability.
[12][13][14][15] Following an announcement by Defence Secretary Grant Shapps at the Sea Power Conference in London, the programme officially received approval to commence with its first phase on 14 May 2024.
[17][18] The ships are envisaged as flexible, multi-purpose amphibious warfare platforms, capable of landing marines ashore via sea and air.
Following the commencement announcement in May, Shepard News reported that BMT could offer their 'ELLIDA' product line whilst Prevail Partners may put forward with their 'Multi-Role Vessel' design.
[24][25][26] BMT have not publicly stated if ELLIDA's general characteristics have changed from those of the first generation design which had (in reference to the 200m variant) a range of 8,500 nautical miles, a service speed of 18 knots and a crew of 68.
In the amphibious role ELLIDA could embark a military force of 350 personnel with an internal 700 lane metres for vehicle stowage, a well-deck for two LCUs, and a hangar for one AW101 Merlin with temporary storage for an additional three.
[28] There is a working deck amidship capable of holding five containers or mission modules, docking stations for uncrewed surface vessels, two boat bays, and has hangar space for two AW101 Merlins.