European gas demand fell by 11% in 2011, its largest ever year-on-year decline, European bank Societe Generale said in a research note.
Europe had mild temperatures in 2011 which reduced demand for gas for domestic heating.
In the UK, 2011 was the second warmest on record, the Met Office said.
SocGen expects gas demand to rise 2.5% in 2012 but for levels before the 2008 financial crisis to be met only in 2018.
"For 2012e, our model shows an increase in gas demand, due entirely to our forecasts being weather neutral (an average 2012e vs a mild 2011).
"Our 1% CAGR [Compound Annual Growth Rate] for 2013e-2018e is in line with what was witnessed in Europe for the period 2000-2010 (1.1%). So, our model sees gas demand reaching pre-crisis 2008 levels only in 2018e, which is not positive for gas demand going forward," the bank said.
The International Energy Agency, Eurogas and BP Statistical Review are yet to publish their data for 2011.
"[They] should publish their first estimates between March and June 2012, but history tells us that they should report numbers close to ours," Soc Gen said.
Figures for the first six months of 2011 released by Eurogas showed a similar trend.
"According to Eurogas estimates, gas demand in the EU decreased by 9% (around 25 billion cubic meters) in the first six months of 2011," Eurogas said.
"The main driver for the decline in natural gas consumption was the mild temperature in the first half of the year, compared with the very cold weather in early 2010," it added.
