Strangled, then beaten: How CPS is replacing its Y2K core
And teaching lawyers how to use Ctrl-F
An agile rollout and microservices have been central to replacing the Crown Prosecution Service’s old case management system – but convincing the department of that wasn’t always a simple task.
The Crown Prosecution Service’s IT team has grown in leaps and bounds in recent years, with only 36 people on board when Gemma Hyde – deputy director of digital and winner of IT Leader of the Year at the UK IT Industry Awards 2024 – joined.
Eight years on and there around 250 people sitting in the Business Information Systems Directorate, with a wide ecosystem of delivery partners.
CPS staff’s technical expertise ranges from the tech professionals in the BISD to lawyers who “didn't even know how to use control-F to find a word in a document.”
The team had to account for both types of user when designing the new Casework App, which is in the process of replacing the 24-year-old Case Management System.
The old CMS relies on a browser-based application with an Oracle database backend and a Microsoft ASP.NET frontend; a standard, if dated, approach.
Additionally, because of the sensitivity of data, third-party applications were heavily restricted in how they could interact with the CMS.
“[After] 24 years it has a lot of features, a lot of bells and whistles that have been added. Originally it was just a document repository and it's been built on and built on and built on.
“It holds all of our workflow, interfaces with all the police forces, interfaces with the court system and does all the workflow in between, as well as being system of record, so it's huge in all senses.”
Fixing funding
Getting the funding model right has been a key element of the work.
“The business case that we've constructed has both the funding for the legacy system and the replacement of the new tools. There's a very real balance of anything we can do to be more efficient around the legacy system means that we can spend more time, energy, money on the new tools.”
The result was "an important cultural shift” in bringing management of both tools under one roof.
“Sometimes there's a tendency to say, 'You look after the legacy over there, and we'll just build the new stuff.' That then means it’s quite disjointed, whereas having them together has been really important.”
Strangling legacy
While the CMS might have been fit for purpose when it was launched at the turn of the millennium, the monolithic app is now a source of inefficiencies.
Even acknowledging that, trying to replace a core piece of technology using a waterfall approach could have created more problems than it solved. Instead, the team opted for a strangler pattern to replace the CMS with the new, purpose-built Casework App.
"We're replacing all the different components that you need to deliver a case management system bit by bit. Day in, day out, our users spend less time in that legacy system and more time in the new.”
Rolling out like this has maintained stability, but Gemma admits, “With hindsight, we weren't ambitious enough with how iterative we were.”
“We very much wanted to launch [the Casework App] in that kind of agile...way. The organisation really wasn't ready for that. They wanted far more features than we'd built and so we felt we were being really ambitious.”
The team had to sit on features they had developed for “a good six months, nine months” before being able to launch them, partly because stakeholders thought they would be getting an unfinished product.
Happily, after seeing the success of the Casework App, most of CPS has come round to the agile method.
“Trying to earn that trust has been really important, and quite hard. But one of our area business managers said to my colleague last month that's how they think all change should be done in the organisation now.
“You could tell people, 'These are the benefits of it,’ but actually hearing them say, ‘I understand the benefits and that's how I want other change to be delivered’? Then you know you've made it.”
From monolith to microservices
Unlike the CMS, the Casework App is built with 21st century design in mind. It was developed using a serverless architecture, infrastructure-as-code principles and CI/CD processes, plus RESTful APIs as a front-end to connect to the old CMS’ GRAPH APIs.
“Okay, there's some legacy associated with that [technology],” Gemma acknowledges, “but the true legacy is what are you actually delivering that’s different for the justice system?”
Perhaps the migration's most outstanding legacy is the speed of delivery.
Under the old CMS, going from user request to delivery could take more than six months. With the Casework App, that’s been lowered to a week, on average – and as little as 90 minutes in some cases.
Gemma calls it “a sustainable way to deliver value more frequently,” pointing out that her team rolls out new features and services every few months.
And for the lawyers who make up the majority of CPS – especially the ones who don’t know how a scrollbar works, or what Ctrl-F does – the Casework App’s impact is already being felt, with an estimated 100,000 hours saved in the last 12 months alone.