ELECTRICITY watchdogs yesterday launched an investigation into the performance of electricity companies during the ''severe disruption'' of supplies over the holiday season, write Aine Harrington and Lorna MacLaren.

The electricity regulator Offer wants to find out why power blackouts occurred for such long periods between Boxing Day and New Year in Scotland and the North of England. It is also to investigate whether better information could have been provided to thousands of customers.

Mr Callum McCarthy, director general of electricity supply, said yesterday: ''Many thousands of customers have had their lives disrupted by prolonged loss of electricity over the Christmas and New Year period.

''I recognise the efforts made by companies to restore supplies, but customers properly want to know why it took so long and why they were unable to obtain better information about what was happening during the power cuts.''

Offer said it had few details on the scale of the power cuts and had requested detailed reports from the power companies about their responses. It will also take evidence from consumers. A report will be issued by March.

Meanwhile, the battle between Scottish Gas and ScottishPower moved up a notch yesterday as the former announced price cuts for more than a million of its customers.

Prices for those who pay their gas bills quarterly are to be cut in March by around 2%. This includes hundreds of thousands of customers who pay all of their bills promptly, and they will see their ''prompt pay'' reduction increase from #31.50 to around #33 a year.

Customers who pay using a prepayment meter will also see their bills reduced by around 1.5 %.

A ScottishPower spokeswoman said: ''This is a sure sign that we are now eating into the Scottish Gas customer base and pressuring them into reducing their prices. We have made no decision to increase our prices to our 230,000 customers and still maintain we offer a cheaper deal to quarterly credit customers.''