Scottish Power plc yesterday became the first British utility to break into the US market, due to a proposed merger deal with Oregon-based PacifiCorp.

The deal will create a group capitalised at more than $19 billion, taking it into the world's top 10 utility companies.

Scottish Power said it would exchange 0.58 of its American depositary receipts or 2.32 ordinary shares for each PacifiCorp share in a deal that values the equity of the US group at around £4.7 billion ($7.79 billion).