Smart meters would need to be installed at a rate of 30-a-minute to meet the government’s target amid a slowdown in the roll-out, Which? analysis has found. The consumer watchdog said energy suppliers would have to fit 30 meters every sixty seconds for the next two years to replace 46 million existing meters by the 2020 deadline.The report comes days before the National Audit Office is due to publish its investigation into the Government’s handling of the costly project which has so far topped £11billion. The public spending watchdog is expected to heavily criticise the project which is running behind schedule and over budget due to technical issues. With just over two years to go until 2020, Which? is concerned that delays and increased costs will result in reduced savings for consumers. Government estimates for the expected savings for an annual dual fuel bill in 2020 have already fallen from £26 to just £11. So far, just 11 million smart meters have been fitted. In February Which? found large energy companies would need to install 24 smart meters per minute to meet the deadline. But rather than speeding up the roll-out, firms have slowed down.Up to 53 million smart meters, designed to replace traditional gas and electricity meters across homes and businesses, are due to be installed across Britain by the end of 2020 with the main energy companies responsible for rolling out 46 million of them. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. Energy suppliers maintain that they will meet the 2020 target, but as the deadline draws closer, experts belive tihs is highly unlikely. Dubbed as the “next generation of gas and electricity meters,” smart meters provide customers with an accurate reading of their energy usage and automatically send this information to suppliers – potentially meaning an end to meter readings and estimated bills.However, the rollout has been plagued with problems from the outset, including faulty in-house display monitors and meters that were no longer compatible when customers switched energy suppliers.Alex Neill, Which? Managing Director of Home Products and Services, said: “The smart meter rollout has been plagued by problems and been massively delayed, the benefits have been overstated and the savings they could bring consumers are at risk. Therefore it’s time for the Government to replan with industry and consumer groups to ensure people get the maximum benefit at the minimum cost.”A spokesman for Energy UK, which represents the energy industry, said suppliers were committed to ensuring all eligible households and businesses are offered a smart meter by the deadline date.”The industry is working hard to reach as many customers as possible and to ensure the roll-out is carried out safely, efficiently, cost-effectively and delivers a positive experience for customers,” he said. “With more than 12 million smart meters now installed in the UK, more and more customers are enjoying the benefits that smart meters bring and are reporting high levels of satisfaction.”Guy Anker, deputy editor of Money Saving Expert, described the entire roll-out process as “a total embarrassment” but said smart meters in themselves were not a bad thing.He told The Telegraph: “This whole saga has been a total embarrassment. There is no way the industry was ever going to meet the 2020 deadline but while the roll out has been completely botched, it is important to remember smart meteres aren’t bad things. “Thecan help you understand your useage better. They have their faults but they can save consumers money.” Earlier this month Npower was accused of coercing customers into getting smart meters as energy companies seemingly feel the pressure of the looming deadline. Valerie Harbidge, 72, from Yorkshire, said she felt “coerced” by the company when she received an email telling her engineers would arrive to install her smart meter in the afternoon of November 22.The email, which had the subject line “your smart meters are coming”, said she could confirm or change her appointment, but did not give her the option to cancel. It told her she had only five days to confirm the appointment.Charity Citizens Advice has raised concerns in the past over the aggressive tactics used by suppliers to encourage customers to sign up for a smart meter. Firms face fines if they miss installation targets.