The building, constructed with a budget of £19 million, opened on 31 October 2013, superseding the former East Sussex Record Office in the county town of Lewes.

[4] Records, documents and objects up to nine centuries old were stored and displayed, such as a letter to the Abbot of Battle Abbey dating from 1101 and bearing King Henry I's seal.

[6] As well as "heavily criticis[ing]" the facility after this second inspection, The National Archives removed most of the licences allowing the county council to store records there.

[7] Although East Sussex County Council had started investigating alternatives in 1996 and undertook a feasibility study in 2004,[8] the project to create a new archive was formalised in April 2006 after the unfavourable second inspection.

Locations at Woodingdean, Newhaven, Lewes, Glynde and two in the Falmer area were examined; one of these was Woollards Field,[9] just inside the Brighton and Hove city boundary on the edge of the Moulsecoomb housing estate.

[10] Public footpaths and a cycle path will be built through the site to connect it with the Moulsecoomb estate and the adjacent road; this was estimated to cost £33,000.

[7] Atkins were chosen as the scheme architects;[20] they have been involved in the design of archive facilities since 1991, including the Berkshire Record Office and the Wiltshire and Swindon History Centre.

[21] Other companies involved with the design and construction process included GTA Civils Ltd, who undertook transport and flood risk assessments; Lizard Landscape Design, who were involved with environmental analysis such as landscape assessments, ecological planning, arboricultural investigation and site photography; Ashdown Site Investigation Ltd, who carried out site contamination analysis; and Archaeology South East (part of the Institute of Archaeology, University College London), who undertook archaeological investigation at Woollards Field.

[25] A grant received in respect of installing photovoltaic electricity generating equipment subsequently increased the available funds to £19,142,000, of which £17,910,000 was allocated to construction and capital expenditure and the remaining £1,232,000 to other costs such as marketing, planning and payments to professionals.

At that time, it was stated that the building was expected to be finished at the end of 2013,[28] although East Sussex County Council's timeline anticipated completion in early 2013 and a public opening later in the year.

[20] Architecturally, The Keep is a rectangular structure with pale brickwork and some rendering, metal-framed windows and doors, a silver metal roof with areas of vegetation and wildflowers, and an "embossed concrete frieze" near the roofline to "create additional visual interest and ... break down the mass of the block".

[26][33] Facilities include lecture rooms, a public reading/study room and similar provision for staff, a recording centre for oral histories, conservation laboratories and areas where archive materials can be repaired, repositories for storage, reprographic and record digitisation facilities, offices, eating and refreshment areas, toilets and a separate Energy Centre.