BP, the operator of the Forties Pipeline System (FPS), could not immediately be reached for comment, but one trader said the restriction was likely linked to work at the Kinneil processing plant, which handles unstabilised crude.

When two trains are offline at Kinneil, the remaining train is normally unable to process all the crude coming through the FPS, depending on shipper demand.

(Reporting by Claire Milhench; Editing by Pravin Char)