M25 J21A Bricket Wood Interchange

Layout and signage

Watford
Harrow
A405
London (NW)
(M1 S Link)
  A405


    A405


  St Albans
A405
London (NW)
(M1 S Link)

Lane configuration

LanesLanesLanesLanesLanesLanes

  • Lane 1 exits and does not return.
  • Lane 2 continues ahead.
  • Lane 3 continues ahead.
  • Lane 4 continues ahead.

LanesLanesLanesLanesLanesLanes

  • Lane 1 is gained from the entry sliproad.
  • Lane 2 continues, with option to exit.
  • Lane 3 continues ahead.
  • Lane 4 continues ahead.

Other events

  • Signs Variable Speed Limits apply
  • Signs Variable Speed Limits apply

In this section

What's new

Farewell GLC lights

Why am I all nostalgic about some street lights being replaced?

Silver bullet

The Silvertown Tunnel is finally open for business. One question remains: what’s it for?

Skid Risk, Accident, Fog

For the first time, we can share pictures of the pioneering experiment that lit up the Worcestershire countryside with enormous signs 61 years ago.

Share this page

Have you seen...

Low Emission Zone

A first step towards emissions-based road pricing, a pointless measure to enforce something that's happening anyway, or another leap forward in traffic planning from the people who created the Congestion Charge? It's hard to say.

About this page

Published

Last updated