(Adds detail on causes of inflation slowdown, comment)
* April CPI +0.2 pct m/m,+2.3 pct y/y; lowest since Jan 2008
* April RPI -1.2 pct y/y, lowest since series began in 1948
* Food, gas, electricity drives CPI down
* Economists expect further fall in CPI
By David Milliken and Sumeet Desai
LONDON, May 19 (Reuters) - British consumer price inflation fell to its lowest level in over a year in April after bigger-than-expected declines in the cost of food, gas and electricity, official data showed on Tuesday.
The Office for National Statistics said consumer prices rose just 0.2 percent last month, taking the annual rate down to 2.3 percent from 2.9 percent in March -- the lowest since January 2008 and below the 2.4 percent expected by analysts.
The broader RPI measure of inflation, which includes falling mortgage interest payments and is used in many wage and benefit agreements, fell to -1.2 percent, the lowest since records began in June 1948.
CPI remains above the Bank of England's 2 percent target but policymakers expect further sharp declines in inflation as the economy is on track to shrink at its fastest since World War Two this year, and are more focused on reviving growth.
The bigger-than-expected fall in inflation also marks a change from the sluggish pace of falls since CPI hit a series record 5.2 percent in September, as sterling's slide against major currencies had muted the benefit of cheaper commodities, which are priced in dollars.
"We're encouraged inflation is starting to come down a little bit quicker and expect it to fall further in the coming six months and fall below 1 percent over that period," said David Page, an economist at Investec.
June gilt futures pared losses after the weaker-than-expected data. The pound was little changed.
LOWER HOUSEHOLD BILLS
The ONS said the biggest downward effect on CPI inflation came from electricity and gas bills as providers cut prices now that oil and natural gas prices have fallen by almost two thirds from last year's record highs.
Food also had a big downward effect with meat and vegetable prices falling this year compared with rises a year ago. Beef, pork, cauliflowers, salad and potatoes were all cheaper. There had been some concern that food prices would keep pushing up inflation given the weakness of the pound.
There was a further negative effect from tobacco and alcohol prices on the CPI rate because annual rises in the duty on these products took place a month later than last year because of the later Budget. This tax rise will feed into May's CPI data.
Communications costs, which have typically helped keep down consumer prices over recent years, were the main upward pressure on CPI in April, after a rise in the cost of renting telephone landlines and buying mobile phone handsets.
Excluding volatile food, tobacco, alcohol and energy prices, core CPI inflation also moderated to an annual 1.5 percent from 1.7 percent in March.
"This suggests that underlying price pressures might be starting to respond to the downturn in the economy and the opening up of a large amount of spare capacity," said Jonathan Loynes, economist at Capital Economics. (Editing by Andy Bruce)