M25 (Holmesdale Tunnels)
- Cubic metres of air per second 370
- Tonnes of ventilation equipment 100
- Annual passengers 5.8 million
The M25 London Orbital Motorway is one of the busiest road networks in the country. Stretching 117 miles, it is the de facto geographical boundary for Greater London. The M25 now carries over 200,000 vehicles a day. After the turn of the century, a £75 million refurbishment scheme was launched by Highways England. It aimed to bring shorter journeys for drivers through additional lanes at junction 25 and through the Holmesdale Tunnel.