The incident was reported next to the Hillbarn traffic lights.
Police said it was ‘causing tailbacks’ and the tanker was ‘likely to be stuck there for a couple of hours yet’.
According to traffic reports, whilst the incident was ongoing, there were delays on A27 Upper Brighton Road westbound between Old Shoreham Road and Busticle Lane (Hilllbarn traffic lights), with an average speed of five mph.
The road has since reopened.
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