Scottish & Southern Energy PLC is to cut its average annual gas bills by 12 pct to 534 stg, the company said this morning.  The cut, which will start from tomorrow (1 March), will be joined one month later on 1 April by a 5 pct cut in the average yearly electricity bill to 355 stg.  The dual fuel rate will therefore be on average 873 stg, a 9 pct cut.  SSE says that the price cut makes them the UK’s cheapest supplier of energy, citing the 873 stg dual fuel bill as 4.6 pct cheaper than E.ON AG’s Powergen and 9.1 pct cheaper than Centrica PLC’s British Gas brand.  It says it will waive any termination fees which may apply to any of its customers who are on its fixed price tariffs to enable them to take advantage of the new tariff without any penalty.  SSE supplies energy as Southern Electric, SWALEC, Scottish Hydro Electric and Atlantic and is the UK’s third largest supplier of energy, and has 7.5 mln customers.  Alistair Phillips-Davies, Energy Supply Director of SSE, said: ‘While wholesale energy prices were rising in recent years, we protected our customers from the worst impacts of the increases, with the result that we have been the UK’s cheapest supplier of energy for most of that period.'’Since last September, we have made clear our intention to cut gas and electricity prices if there was a sustained fall in wholesale prices which would allow us to do so, and so I am very pleased that we have now been able to make this announcement. It means we are able to start cutting prices immediately.’