Britons could be given shopping vouchers, discounts and free treats for walking just 20 minutes per day in a plan backed by the NHS.The incentive scheme, led by Olympic medallist Sir Brendan Foster and Air Miles inventor Sir Keith Mills, will be launched in January in a bid to get the nation moving again.Millions will be urged to reach a target of 20 minutes per day because that roughly equals around 26.2 miles over the course of a month - the same distance as a marathon.Health officials are said to be in discussions with retailers over creating a loyalty programme potentially rewarding people with free coffees and cinema tickets for meeting the walking targets.The campaign, named Movement 26.2, is expected to be delivered through an app or website.Users may also be able to earn digital badges and medals, similar to the reward systems deployed by popular apps such as Duolingo and Strava.Sir Brendan told The Telegraph: 'Our formula has always been: encourage, challenge, support and reward. Initially there'll be digital rewards, like keeping a streak going for three months. 'Over time there'll be other kinds of rewards – medals, T-shirts, but also discounts and rewards.' Britons could be given shopping vouchers and discounts for walking just 20 minutes per day in a plan backed by the NHSAdults in the UK are currently encouraged to exercise for 150 minutes per week in line with World Health Organisation guidance. But only around half of middle-aged Britons manage just one brisk 10-minute walk a month.Low physical activity levels are estimated to cost the UK £7.4billion a year, including around £1billion in NHS spending.This is largely because sedentary behaviour can lead to serious health complications such as cancer, obesity, heart disease and type 2 diabetes.Sir Brendan, who also founded the Great North Run - the world's largest half-marathon - said they are now trying to create the 'biggest marathon in history, but one that's open to absolutely everybody'.He added: 'It's the marathon reimagined. You don't have to travel anywhere, you don't need special kit and there's no entry fee. It starts from your own front door.' The initiative also draws on Sir Keith's experience creating the hugely popular Air Miles rewards programme, which allows frequent flyers to collect points that can be redeemed for flights, upgrades, hotels, car hire, airport lounge access and other purchases.NHS England chief executive Sir Jim Mackey said: 'Physical activity should be part of everyone's daily life choice. Movement 26.2 is about exactly that – making movement part of everyday life again in a way that feels simple and achievable for everyone.'By helping people build regular walking into their daily routines, we have a real opportunity to improve physical and mental wellbeing and help people live longer, healthier lives.'The incentivise scheme will be led by Olympic medallist Sir Brendan Foster (left) and Air Miles inventor Sir Keith Mills (right)The concept has already been tested on a smaller scale in Ebbsfleet, where participants were rewarded with vouchers for local shops and free coffees for walking and cycling, paving the way for a national rollout.But not all experts are convinced.Dr Bismillah Sehar, a lecturer in public health at Birmingham City University, said: 'Every movement counts and small consistent changes can lead to significant long-term health benefits.'Initiatives that encourage people to incorporate walking into their daily routine have the potential to support healthier behaviours and reduce the growing burden of preventable disease on the NHS.'However, initiatives alone are unlikely to be sufficient. They need to be a part of a broader strategy that addresses the barriers many people face, including safe walking environments, access to green spaces, time constraints, and socioeconomic inequalities.'The NHS already recommends taking a brisk 10-minute walk every day, saying it delivers a range of health benefits.A review by Public Health England found that adults who walked for just 10 minutes a day improved their physical fitness and mood while reducing their risk of early death by around 15 per cent.Separate research by the University of Leicester suggested that even modest increases in daily walking could extend life expectancy. The 2024 study found that a brisk walk at around 3mph for 30 minutes a day could add almost a year and a half to women's lives and as much as two and a half years for men.