The fire service said it was called at 10.19pm to a layby on the A22 between the Cop Hall and Eagle roundabouts, to reports a van was on fire.
A fire engine was sent from Eastbourne, and the crew used one breathing apparatus and one foam to put it out.
Police also attended the scene.
The fire was treated as deliberate, a fire service spokesman said, and the incident was being investigated by officers.
The road did not need to be closed while the fire was brought under control.
The fire service left the scene at 11.10pm.
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The scene of the fire. Picture: Dan Jessup
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The scene of the fire. Picture: Dan Jessup
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The scene of the fire. Picture: Dan Jessup
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The scene of the fire. Picture: Dan Jessup