Smokers should be permitted to use e-cigarettes on NHS sites, leading doctors have said.
Meanwhile, smoking cessation services should be an "opt out" element of a smoker's NHS care, according to a new report on how the NHS treats smoking addiction.
Such a move could double quit rates, the authors said.
The report from the Royal College of Physicians (RCP) also calls for e-cigarettes to be used on NHS sites to support smokers to remain smoke-free.
It said that at present smokers are admitted and discharged without being asked if they are a smoker or offered help to quit.
The report also calls for new legislation requiring hospitals to implement completely smoke-free grounds because adherence to current guidance is "patchy".
Meanwhile the RCP, which is currently hosting its Innovation in Medicine conference in London, has also called for all healthcare training to include information on smoking cessation.
It said that stop smoking services delivered separately from mainstream NHS services "may now not be the best approach".
In England, responsibility for these services was transferred to local authorities in 2013 and funding has since fallen "dramatically", it added.
"Treating the more than one million smokers who are admitted to hospitals every year represents a unique opportunity for the NHS to improve patients' lives, while also saving money," said Professor John Britton, chair of the RCP's Tobacco Advisory Group and lead editor of the report.
"For too long the NHS has failed to take responsibility for smoking, while prioritising other, less effective activity.
"Smoking, the biggest avoidable cause of death and disability in the UK, is hiding in plain sight in our hospitals and other NHS services; the NHS must end the neglect of this huge opportunity to improve our nation's health."
Commenting on the report, Duncan Selbie, chief executive at Public Health England, said: "One in four hospital patients are smokers costing hospitals £1 billion a year.
"We fully support the Royal College in saying by far the majority of the NHS could be doing more to help smokers to quit."
Izzi Seccombe, chairwoman of the Local Government Association's Community Wellbeing Board, said: "It is right that the NHS focuses more on helping smokers to quit but not at the expense of resources transferred to councils from the health service - local authorities remain best-placed to help tackle the health and wellbeing inequalities that exist in their communities.
"Councils remain committed to working with the NHS to help smokers quit, however this is made all the more difficult by a £600 million reduction to the public health budget by central government between 2016/17 and 2020/21, which will only compound acute pressures for NHS services further down the line."
Simon Clark, director of the smokers' group Forest, said: "Providing smoking cessation services to patients in hospital is at best a questionable use of public money.
"Smokers contribute £12 billion a year in tobacco-related taxes. That far exceeds the estimated cost to the NHS of smoking by patients and staff.
"Smoking is a choice and if adults choose to smoke they shouldn't be pestered to quit while in hospital."