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Portsmouth City Council: Large Panel System case study

This case study explores how Portsmouth City Council were able to deliver the demolition of Horatia House and Leamington House, which were two 18-storey blocks constructed using Large Panel Systems.

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This case study explores how Portsmouth City Council were able to deliver the demolition of Horatia House and Leamington House, which were two 18-storey blocks constructed using Large Panel Systems. The council undertook a very thorough public engagement exercise, which led to the development of a comprehensive communication strategy that the council used effectively to engage with stakeholders throughout the demolition and redevelopment of the two blocks, and particularly throughout the challenging process of decanting residents.


Portsmouth City Council owned two large panel system tower blocks in close proximity to each other. Horatia House and Leamington House were two 18-storey blocks that included a total of 272 well-occupied flats which formed part of the wider Somerstown estate in Portsmouth City. 

The flats were constructed in the mid-1960s, both constructed utilising precast concrete, using the Bison Wall Frame system. The method of constructing Large Panel System (LPS) buildings has been a cause for national concern due to the inherent risk of partial or complete collapse. 

Specifically, LPS structures are at a higher risk of collapsing from internal gas explosions. Tragically, this risk became a reality in May 1968 when the Ronan Point tower block partially collapsed due to an internal gas explosion. The extent of the damage was greater than expected for an explosion of that magnitude, prompting the government to reassess LPS blocks across the UK. This led to several circulars and revisions to building regulations and the national wind code issued by the Ministry of Housing.

In response to the findings from the investigation into the Ronan Point collapse, the council undertook strengthening work in the mid-1970s to the blocks, this included measures to improve the panel stability reducing the collapse risk. 

Due to the national focus on tower block safety, the council carried out several inspections and investigations on the blocks which led to some significant remedial works including external panel replacements, refurbishment works and over-cladding. 

The council undertook an energy efficiency project for a local lower-level multi-storey block to improve the insulation of the building. Due to this project’s success, it was decided a strategy was agreed to undertake further feasibility studies to identify whether the project could be replicated in the neighbouring LPS buildings. 

The risk that needed to be addressed 

A review of the existing cladding and fire safety presented problems that required considerable work to be rectified, having removed the ACM cladding a feasibility study to reclad the buildings and identify the potential of energy efficiency works was undertaken. As part of the feasibility a structural survey was commissioned to understand whether the buildings could take the extra weight of the proposed insulation. It was uncovered that the quality of the initial construction was not as strong as initially expected, presenting concerns about the future viability of the blocks. This led to the difficult decision to vacate the blocks due to safety concerns.

The council conducted a thorough analysis of various options to determine the best course of action for the blocks. These options included refurbishing the blocks, selling them, or demolishing them and selling the land. The analysis revealed that refurbishing the blocks would be a costly endeavour, estimated to be around £81-£86 million. Moreover, the complexity and risks associated with the refurbishment project made it unappealing to contractors. Even with the refurbishment work, the superstructure would only have a remaining useful life of 30 years, which did not justify the significant financial investment required.

Based on these findings, the council made the decision to demolish the blocks. This option provided an opportunity to redevelop the site. While demolition is also a costly process, it is considered to be a more financially feasible option in the long run. Overall, the decision to demolish the blocks was based on a thorough analysis of the available options, taking into account both the financial and practical considerations involved.

Highlighting the change

The initial priority of the project was the residents of the two tower blocks and the short notice decant of over 250 residents for safety reasons, this was a particularly challenging situation that was managed very well by the council.

The process of decanting residents was divided into several stages, including:

  • planning and mobilisation
  • informing tenants and staff
  • planning and carrying out moves
  • making it business as usual
  • finishing the decant. 

During this process, a dedicated support team, within the council, was located at the Civic Offices. They coordinated an emergency response and supported any residents who had concerns about the safety elements of the blocks and required emergency temporary accommodation.

Effective communication was a crucial element during the decanting process. A communications strategy was carefully planned to ensure that tenants were the priority. Communications were prepared in advance, including frequently asked questions, a dedicated webpage on the council's website, a range of letters targeted to specific audiences, and a media briefing/media release. Additionally, regular letters to tenants, drop-in sessions, meetings with housing officers, and updates to councillors were provided throughout the project. 

It was important that every tenant had the ability to have one-to-one conversations with a member of staff who listened to their concerns. By doing this, support was able to be focused on the most vulnerable residents. Interpreters were on hand and available for any meetings. 

Officers met 182 tenants on the first day of consultation, and within the first week they had met all tenants in Horatia House and all but 23 in Leamington House. They worked in the evenings and weekends to ensure that all tenants had been reached. The FAQs included in the letter advised that one offer of accommodation would be made to each household to minimise unfounded fears arising outside of the main blocks. The project team and managers were proactive in their approach, and effective communication played a crucial role in making the process smoother for all involved.

Following the successful decant of Horatia and Leamington House, housing officers carried out a survey of residents to find out their views on how well all aspects of the decant worked from informing residents to being rehoused. This allowed the council to collect valuable feedback which will support future council decants. 

Portsmouth is the most densely populated city outside of London and the proposed demolition of two 18-storey tower blocks would impact a number of local businesses, residents and community organisations. The council’s engagement and communication exercise had to be very thorough. 

There were 1,456 households and 25 businesses within a very local area of the two blocks. In addition to the residents and businesses, the council identified several other stakeholders who needed to be engaged with the demolition and redevelopment, this included:

  • University of Portsmouth
  • Portsmouth Disability Forum
  • primary and secondary academy schools
  • Hampshire fire and police services
  • residents’ consortiums
  • community centres.

The council undertook a very thorough public engagement exercise that followed five key themes:

  • Identify our stakeholders
  • Give them the facts: No empty promises, clean non-negotiables, plain English
  • Let them have their say
  • Listen
  • Act on what they say.

This led the council to create communication channels that were available to everybody via dedicated email addresses, postal addresses and a web page that included all the key details of the schemes. The council were conscious of the demographic of the area and ensured the communications catered to all languages, reading ages and levels of digital confidence. 

The council also held public drop-in sessions, where residents were encouraged to attend to share any thoughts or concern they may have had with the proposed development. Due to the focus tower blocks received from the local fire services, early engagement was held with the Hampshire fire brigade to ensure they were aware of the proposals and were also provided with an opportunity to feedback on the details.

Lessons learned

Early in the redevelopment process, the council recognised the impact it would have not only on residents but on the wider community. As a result, the council conducted an exercise to identify all direct and indirect stakeholders, allowing them to create a communication strategy that met the specific needs of each group.

The council's comprehensive communication strategy ensured that all voices were heard, with measures such as drop-in sessions at varying times and accessible communication methods catering to all demographics. Initially a dedicated 24-hour team was also available to answer any questions and keep residents informed about the scope and pace of the decant process.

By engaging, informing, and listening to residents, the council ran the demolition project efficiently, the engagement with all stakeholders regarding the redevelopment will result in a high-quality outcome that will benefit the local environment of the Somerstown estate.