Average UK house prices remained flat across the first three months of 2012, according to new figures from the Halifax.House prices showed a decline of 0.1%.in the first quarter of 2012 compared with the final three months of 2011 and were 0.6% lower than in the same period last year.There was a 2.2% rise on average in March following February's 0.4% fall, something the lender put down to a rush by first-time buyers to beat the expiry of the stamp duty holiday at the end of the month.The number of completed house sales rose to its highest levels since late 2009, although there will be fears this will drop off now the 1% stamp duty on properties costing £125,000 - £250,000 is back in place."The more volatile monthly figures continue to fluctuate as a result of the historically low level of sales volumes," Halifax said."We continue to expect little overall movement in prices this year provided that the UK economy does not suffer a pronounced weakening."The average UK house price is at the same level as in July 2011, Halifax said. Its figures show the UK average price in March 2012, at £163,803, was almost identical to the July figure of £163,765. "Owing to the volatility in the monthly series, the MPC's preferred house price measure is the average of the three month to three month growth rate across the Halifax and Nationwide surveys," said Blerina Uruci from Barclays Capital. "This [measure] showed a 0.2% decline in March and the sixth consecutive month of price declines, suggesting that conditions in the housing market have softened in recent months," she said.