Six miles of tailbacks are reported due to a stalled crane on A27 Westbound, before Carden Avenue.
The incident is congested to the Southerham Roundabout, according to reports.
Lane one (of two) is closed towards Worthing.
At 6.30pm, Highways England tweeted the following update: “The earlier broken down crane on the A27 westbound between A270 and A23 remains in situ.
“Lane one (of two) will need to remain closed until recovery is complete.
“Westbound traffic on the A27 is currently slow on approach with approximately 30 minutes delay.”
More to follow.