February saw the biggest peacetime evacuation the UK has seen since the Second World War, when a live bomb was found in Plymouth. While all councils regularly test civil protection plans, few have to put plans into practice on such a large scale, so we want to share our experience.

As a coastal city with a rich naval heritage, we are used to unexploded bombs. We have a large naval base at Devonport, so when devices are found, the navy bomb disposal team assist without too much drama.

On Tuesday 20 February, the 70-year-old Second World War bomb was found in a garden in Keyham and the bomb disposal team were concerned about the device's stability and their ability to remove it safely.

City response

The council's emergency response arrangements were activated. A multi-agency Strategic Co-ordinating Group (SCG) and Tactical Co-ordinating Group (TCG) was set-up that day with supporting internal gold and silver arrangements.

Multi-agency cell groups were set up to look at evacuation, volunteers, communication, rest centre arrangements and recovery. Each had regular meetings, all reporting up to the SCG for key decision-making.

While the Navy swiftly put in a 309-metre cordon around the bomb, we helped source 300 tonnes of sand to pack the area around the device and 3,250 residents were evacuated. It became clear very quickly that people would not be able to return that night.

Working with our partners, we set up an accommodation area at a community centre. It was staffed by both organisations and offered information and support. The brief was to keep people safe and offer a place for them to go if they had nowhere else.

We then looked at night-time arrangements. Most people could stay with friends and family, but many could not.

We wanted to make sure everyone had a proper bed. We set up a helpline and found hotel, bed and breakfasts and Airbnbs for anyone who was stuck. By midnight, everyone who came to us and said they had nowhere to stay, received accommodation.

We also needed to understand which residents were known to us within the cordon – older and vulnerable people, those with disabilities or children we support. We contacted them to see if they needed help with accommodation, equipment or transport.

The next day brought worrying news. The bomb disposal experts informed us they did not think they could safely detonate the device without catastrophic damage to at least four houses.

We had a family liaison officer speak to residents in the most impacted properties. The conversation was difficult. We needed to strike a balance between compassion and practicality – how could we support those who might lose their homes?

We offered a removal service to empty their properties and their personal belongings were put in storage. That way, the damage would be to bricks and mortar only.

When it became clear the incident would not be over that day, we moved our rest centre to a leisure facility. We closed it to customers and provided a large space, refreshments, prayer room, children's play area, etc. Council staff and volunteers supported it and as we moved into the second night, our offer of accommodation continued.

Thursday was a game-changer. As the day progressed, further assessments of the device came in. The experts had underestimated the damage of a controlled detonation on site. Rather than four houses, they were looking at a much larger number – nearly all the properties within the cordon could be damaged.

With the police, we pushed the experts to revisit their plans and come back with another option. We were looking at a huge hole being created and that was unpalatable.

At 11pm on Thursday night the experts proposed another option. They could move the bomb, but they would need an extended cordon surrounding the route.

Overnight, council officers with key agencies worked solidly on an action plan to evacuate an additional 7,070 people from 2pm to 5pm the next day.

We put together highways, communications and door-knocking plans. By 9am we had an outline which was scrutinised at TCG before going to SCG for approval. By 11am a decision was made to evacuate.

We used the Government's Emergency Alert System – the first since its test in 2023 – and this was sent to every mobile phone in the area.

We carried out media interviews and sent e-newsletters and social media posts. More than 200 volunteers knocked on doors, handing out factsheets asking people to leave their homes before 2pm.

At 2pm, and every half hour after, SCG checked the percentage of households cleared. By 4.30pm every property had been visited. With 134 people refusing to leave and the police having no legal power to forcibly remove them, SCG had to decide whether the Army could proceed.

Legal advice made it clear we needed to demonstrate that all those refusing to leave home understood the risks.

The city held its breath while the 45-minute operation took place. The roads were empty and silent as the bomb was carefully moved from its resting place, travelled through the streets, passing the naval base and on to the water's edge and then out to sea for disposal.

When the all-clear was given, communications once again went out – the cordon was lifted and the roads reopened, enabling people to return home.

While most people could return to normality, for the four original houses, the recovery journey had just begun. Their houses had been trampled, things were broken and 300 tonnes of sand needed to be removed. Work to support these residents continues.

I am proud of my colleagues. People worked tirelessly, with compassion and kindness. They worked at pace, problem-solving and most importantly, as part of a team. It sums up the importance of local councils in an emergency and the way we came together with our partners was fantastic.

What advice would we give others?

We were lucky. The bomb did not go off. No one was hurt and all properties were left standing. But I do have some takeaways for others faced with a similar dilemma:

• Don't forget you have civil contingency plans. That should be your starting point
• Bring your TCG multi-agency group together as early as possible
• Have a structured battle rhythm in place early, with dedicated admin support for each group. Going from meeting to meeting leaves no time for briefing
• Make sure you have a regular drumbeat for updating members and identify your talking head as soon as possible
• Have someone with a helicopter view of the whole thing and ensure everyone is clear who that is. It could be your civil contingencies lead, but it needs to be someone who does not get bogged down in issues. They need to be the orchestra conductor and ensure everyone is playing the same tune
• Have your communications machine in place. Ensure communication gets issued early and regularly. Say something, even if there is not much to say. Communicate with your staff, not just to residents
• Remember staff wellbeing. Many of our staff were personally impacted by the incident
• Stand back. Take a breath. It is very easy to get carried away. Be considered and clear with every action and decision. Think things through.

Tracey Lee is chief executive of Plymouth City Council

X – @plymouthcc

The Plymouth bomb removal operation: facts

• Supporting the evacuation of 10,320 people

• Setting up and staffing two rest centres for more than 1,000 people across three days

• Supporting the Army, implementing road closures, sourcing 300 tonnes of sand

• Supporting residents closest to the bomb site

• Communicating with residents – creating an online ‘incident hub' with regular updates (more than 73,000 views), a postcode tracker for people to see if they were being evacuated (used by 3,000 people) social media, arranging dozens of media interviews and utilising the Government's alert system

• Setting up and staffing a 24-7 helpline (nearly 1,000 phone calls in three days)

• Supporting vulnerable residents to evacuate – providing transport and equipment. This included evacuating an adult residential care home

• Arranging temporary accommodation for 180 households

• Helping six schools and nurseries to evacuate