Installation

The GOV.UK theme contains full compiled CSS and works out-of-the-box. You only need Node.js if you want to modify and compile the theme’s Sass files.

The current v3.1.x branch of GOV.UK Theme targets GOV.UK Frontend v6.

Detailed install for Ubuntu / Debian / macOS

The following steps work for Debian/Ubuntu and macOS. On Windows, install Node.js from the official website: https://nodejs.org.

1. Check Node.js and npm

node -v
npm -v

2. Do not install Node.js using apt

If you see:

Command 'node' not found, but can be installed with:
sudo apt install nodejs

Do not do this. Distribution packages are often outdated and may not meet GOV.UK Frontend requirements.

3. Install Node.js LTS using nvm (recommended)

Install nvm (Node Version Manager) using the instructions at:

https://github.com/nvm-sh/nvm

Then install the latest Node.js LTS:

nvm install --lts
nvm use --lts
node -v
npm -v

You should now see a recent Node.js version (for example v24.x). npm is included with Node.js.

4. Install theme dependencies

Switch to the GOV.UK theme directory, for example:

cd web/themes/custom/govuk_theme

If a package-lock.json file exists, run:

npm ci

Otherwise run:

npm install

This installs GOV.UK Frontend v6 and all required build dependencies.

Important: Sass compiler requirement

GOV.UK Frontend requires Dart Sass (sass) v1.79.0 or newer. LibSass (node-sass) is not supported.

npm ls sass
npm install -D sass@^1.79.0

Compiling Sass (Gulp)

The theme includes Gulp locally. You do not need a global install.

npx gulp

To automatically compile Sass on changes:

npx gulp watch

Updating dependencies

npm outdated

If packages are listed, update within the allowed version ranges:

npm update