Less than three in five people who set a date to quit smoking through NHS services in North Somerset successfully did so last year, new figures suggest.
The charity Action on Smoking and Health said stop smoking services make a key difference in people's ability to quit but warned councils who partly operate them lack long term funding.
It comes as a study found smoking rates increased in some parts of the country over the past four years, after more than a decade of decline.
NHS England figures show 223 of the 397 people who had set a date to quit smoking in North Somerset self-reported they had done so between April and September 2024.
It means 56% of attempts to quit smoking using stop smoking services in the area were successful.
Across England, 105,954 people tried to give up smoking during that period, while only 57,472 (54%) successfully quit.
Dr Ian Walker, executive director of policy and information at Cancer Research UK, said while "stopping smoking completely is the best thing you can do for your health", these figures show it remains hard for many people across England to do so.
He added the financial pressures faced by NHS England, which also operates stop smoking services, must not affect support provided to help people quit as "tackling smoking must be a key priority as our health services evolve".
He said the Tobacco and Vapes Bill, which will be discussed in Parliament on Wednesday, "is a crucial opportunity for the Government to shield society from the devastating effects of smoking".
The figures also show significant differences in success across the country last year, with 64% of those who set a quit date reporting they were successful in Yorkshire and The Humber, compared to 41% in the West Midlands.
Meanwhile, research by the University College London found regional differences in smoking uptake across England narrowed over the last two decades.
The study shows the proportion of the population smoking in England decreased from 25% in 2006 to 17% in 2024, though progress began to stall in 2020 and smoking rates increased again in some regions, including the South West, South East and London.
John Waldron, policy and public affairs manager at ASH said: "Research shows that people who use stop smoking services are around three times more likely to quit than those who try using willpower alone.
"Cigarettes are extremely addictive and so the most effective approach combines specialised behavioural support from a local stop smoking service with stop smoking aids like medications and vapes."
He added the stark difference in quit rates across England "needs to be addressed" and called on the Government to develop regional tobacco control offices across the country which have proved "highly effective at coordinating local activity and driving up standards".
He also said councils are limited in their action to help people quit smoking by a lack of long-term funding, and called for tax rises on tobacco manufacturers to fund stop smoking services.
A Department of Health and Social Care spokesperson said: "Giving up smoking is one of the best things you can do to improve your health. These findings show fewer lives are being lost to smoking, but there is still work to do.
"The landmark Tobacco and Vapes Bill will create the first smoke-free generation and put us on track to a smoke-free UK.
"Alongside the Bill, we are supporting current smokers to quit. We're investing an extra £70 million for local stop smoking services this year and working to ensure all NHS hospitals offer 'opt-out' smoking cessation services into routine care."