Eco runs from January 2013 to March 2015 and suppliers have so far been set initial targets for the first 15 months, to March 2014.
Yet nine months in, as of the end of September, British Gas was just 9pc toward its initial target for helping poor and vulnerable customers – a lower proportion than any other major supplier.
The company announced a 9.2pc price rise last month, claiming that Eco – which already accounts for about £50 on a household bill – would add a further £40 per household next year.
Yet it had completed just 4pc of required measures for hard-to-treat homes and 6pc of community energy-saving measures. On these targets its performance is second-worst only to nPower among the Big Six.
nPower, which raised prices by 10.4pc, had completed just 2pc of required community energy-saving measures by the end of September and just 3pc of measures in hard-to-treat homes. It was 18pc toward its targets for helping the poor and vulnerable.
SSE, which raised prices by 8.2pc, had completed just 13pc of the vulnerable customers target, 8pc of hard-to-treat homes and 18pc of community measures.
By contrast E.On, which is now expected to raise prices in the New Year, by a lesser percentage than its rivals, is ahead of its rivals on all three targets, having completed 74pc of measures for vulnerable customers, 62pc of community measures and 26pc of measures in hard-to-treat homes.
The initial targets for the 15 months to March 2014 represent about 60pc of the total measures companies will be required to hit by March 2015. If they fail to meet final targets then they could face fines of up to 10pc of turnover.
A British Gas spokesman said: “British Gas has entered into contracts worth over £900m with a range of partners including more than 60 local authorities and housing associations, which is more than any other energy supplier.
“Government data shows our costs to date are in line with average industry costs. We are firmly on track to meet the March 2015 deadline, and have agreed a number of large schemes across Britain that are helping to make homes warmer and transforming communities, as well as creating jobs. The Ofgem data do not show the accelerating pace of our Eco delivery.”