Motorway sliproad roundabout sign
A blue sign with a diagram showing a roundabout at a grade-separated junction, with exits left and right, and the following text.
Left turn destinations: (M1); London; NW & C) ; Harrow; Watford; A405 [Hollow square diversion symbol].
Right turn destinations: Hatfield; St Albans; A405.
A left turn here gets us on the A405 westbound.