The problem
The BBC News mobile experience was suffering from performance issues that impacted user engagement and accessibility. Initial page loads took over 8 seconds on 3G connections, and the Time to Interactive (TTI) metric averaged 12 seconds. This created a frustrating experience for millions of daily readers, particularly in regions with slower network connections.
Key pain points included:
- Heavy JavaScript bundles blocking initial render
- Unoptimized images causing layout shifts
- Third-party scripts impacting Core Web Vitals
- Inconsistent component patterns leading to bloated CSS
My approach
I led a comprehensive performance audit and redesign focused on three core principles: speed, accessibility, and maintainability.
Performance optimization
- Implemented critical CSS inlining and deferred non-essential styles
- Reduced JavaScript bundle size by 60% through code splitting and lazy loading
- Introduced responsive images with modern formats (WebP, AVIF) and proper sizing
- Optimized font loading strategy using font-display: swap and preload hints
- Established a performance budget enforced through automated testing
Design system refinement
Created a lightweight component library built on semantic HTML and progressive enhancement. Each component was designed mobile-first with performance as a primary constraint. We standardized spacing, typography, and color systems to reduce CSS bloat while maintaining brand consistency.
Accessibility improvements
- Ensured WCAG 2.1 AA compliance across all pages
- Improved keyboard navigation and focus management
- Enhanced screen reader experience with proper ARIA labels
- Implemented skip links and landmark regions for better navigation
- Increased color contrast ratios throughout the interface
Results
The redesign delivered measurable improvements across all key metrics:
- First Contentful Paint: Reduced from 4.2s to 1.1s (74% improvement)
- Time to Interactive: Dropped from 12s to 3.8s (68% improvement)
- Lighthouse Performance Score: Increased from 42 to 94
- Bundle Size: Decreased from 420KB to 168KB (60% reduction)
User engagement also saw significant gains:
- 23% increase in page views per session
- 18% reduction in bounce rate
- 31% improvement in mobile conversion rates
The new design system reduced development time for new features by approximately 40%, with better consistency and fewer bugs. The project established performance best practices that were adopted across other BBC digital properties.