Inchcape plc is set to abort its plan to privatise its Singapore-listed subsidiary Inchcape Motors after a key shareholder announced it would block the bid. British investment company Guinness Peat Group, which has been mopping up Inchcape Motors' shares, said it will reject Inchcape plc's conditional cash offer of £GB0.90p a share to turn Inchcape Motors and its motor distribution business into a 100 per cent privately owned company.