npower hikes prices: what next?

This morning npower announced it would be raising its prices - and unveiled the biggest increases so far. Dual-fuel bills will rise 10.4% - including electricity price rises of 9.3% and gas price hikes of 11.1%. The change will take place on 1 December - adding an average of £135 a year to the average dual fuel bill.

So what is going on? Why are prices rising, will the other providers follow suit, and what can you do?
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