FOUR in ten battery-powered smoke alarms failed to activate during house fires last year.
And experts say the figure has remained largely the same for almost a decade.
They are urging homeowners to test their alarms in the run-up to Christmas as decorations and candles increase fire risks.
Analysis of Home Office statistics show 38 per cent of battery-operated alarms failed to go off during fires — 20 per cent due to missing or faulty batteries.
But in 45 per cent of cases, they failed because the smoke did not reach the alarm.
Research also found 21 per cent of mains-powered alarms failed in the last year.
Industry stats suggest ten per cent of households do not have a working alarm and 22 per cent have never tested their device.
Ian Stephens, from the Local Government Association, which carried out the analysis, said: “These worrying failure rates are a reminder to people to test their smoke alarms and change batteries where necessary.”