The number of children admitted to hospital suffering respiratory infections has plunged by 11,000 a year since England introduced a ban on smoking in public places, new research has shown.

After the ban was introduced, in 2007, there was immediate 3.5% drop in admissions among under-15s and a nearly 14%, fall among those suffering chest infections.

The findings of researchers from Edinburgh, London, the Netherlands and the US., published in the European Respiratory Journal, reveal that the fall in admissions is saving the NHS about £17m ($26m) a year.

The study also confirmed that the greatest impact of anti-smoking laws on children's health was greatest on those from the most deprived families.

Lead author Jasper Been, from Edinburgh University, said: "Our results add to the growing body of evidence demonstrating the benefits of smoke-free legislation. Although our results cannot definitively establish a cause and effect, the rigorous analysis clearly shows that the introduction of smoke-free legislation was associated with significant reductions in hospital admissions among children."

Aziz Sheikh, co-director of the university's centre for population health sciences, said: "When you look at the results of this study alongside national data showing a decrease in smoking within the home, the findings greatly strengthen the recommendations for the global implementation of legislation prohibiting smoking in public places. We urge other nations to consider introducing and enforcing smoke-free legislation in order to protect the health of children – the most vulnerable members of society."

Nick Hopkinson, honorary medical adviser of the British Lung Foundation, told The Guardian: "We now look forward to the implementation in October of the ban on smoking in cars carrying children. Every child protected from exposure to second-hand smoke is a victory, and this law will be a significant further milestone for public health."