The massive exercise will involve a new corporate logo for the group and rebranding thousands of BP petrol stations in the US under the Amoco name.
The last BP makeover in 1989 cost the group pounds 100m and involved redesigning the company logo and introducing the now-familiar green-on-yellow colour scheme. On that occasion, all BP's 19,800 petrol stations were given a facelift along with its fleet of tankers.
This time the existing BP brand will be retained on all its petrol stations outside the US. The 6,500 US stations either trade under the BP name or are run by independent retailers. All these BP-branded stations will be converted to Amoco outlets.
BP will have to amend its branding on all stationery and offices round the world, where it will be known under the corporate name of BP Amoco. A spokeswoman said it had not yet decided whether to create a new corporate identity or run the two logos side by side.
BP is considering whether to employ design consultants. If it does the costs could escalate. The makeover of British Airways, featuring the controversial tail fin designs, cost pounds 60m. The rebranding of Cable & Wireless Communications, a merger between Mercury Communications and three cable companies, cost pounds 50m.
The BP Amoco merger is already costing around $100m in fees mainly to the companies' respective investment banking advisers, JP Morgan and Morgan Stanley, and $500m is budgeted for restructuring measures, the biggest cost of which is 6,000 job cuts from the combined workforce of 100,000.
Chris Lightfoot of Newall and Sorrell, the corporate identity specialists who did the BA makeover, said: "You have to approach corporate makeovers very carefully these days because of the cost and scale and people's sentimental desire to hang on to things when the world is changing so fast. But BP has got to communicate the shift in some way."