By Jane Dreaper
BBC News, Health correspondent
How should the authorities treat people with infectious diseases who might put others at risk?
It was once thought outdoor therapy was good for TB patients
This tricky question is being considered by health officials in England. Their consultation about new laws on the control of disease and other hazards closes this week.
Parts of the legislation date back to Victorian times and have suitably archaic wording.
Experts agree that a new approach is needed - but some people are worried that the government's proposals for change are too vague, and potentially draconian.
It is easy to think of tuberculosis (TB), for example, as a disease of the past.
"People today are leading much healthier lives than they used to. They're therefore stronger and fitter and don't become consumptive," proclaimed Lord Astor in 1934.
This was at a time when deaths from TB in this country had dropped - though there were still 34,000 - thanks in part to treating people in sanatoriums.
Lord Astor added: "They are made to sleep with open windows - instead of in stuffy rooms, though some of them hate this at first."
TB is still with us. A drug-resistant form of the disease recently reared its head in the US, forcing officials to issue their first quarantine order in 44 years.
The infected man remains in hospital, ahead of lung surgery next month.
Bird flu is viewed as a potential threat
Quarantine sounds extreme - but in fact about a dozen times a year, magistrates in the UK order people with an infectious disease to be detained in hospital.
Dr Graham Bickler, the Health Protection Agency's regional director for the south-east, said: "Typically this will be someone who has got active TB and is an active risk to others.
"A range of things will have been tried to deal with them. There is no power to treat them - there is only a power to keep them in a place where they are not a risk to the public."
The current legislation refers to rag and bone men, and penalties of £2. Dr Bickler agrees with many experts that a fresh approach is needed.
"It is about a world which has clearly long passed," he said.
"Its powers are inappropriate. It talks about infectious library books and common lodging houses. It is just completely out of date."
I took a train to Gravesend in Kent - accompanied by the director of port health for the City of London, Jon Averns.
For 150 years, this authority has been in charge of health issues on the River Thames - making sure, for example, that infectious diseases don't enter the UK via ships.
Gravesend has always been a base for the authority - and in the past it is where medical officers boarded ships to carry out checks.
There is still a launch at Gravesend, so patients can be taken ashore if necessary.
Mr Averns said: "We've only had a handful of cases in the past year. They have involved everything from malaria to food poisoning and hepatitis.
"But the concern is that you only need one really big case to spark off a pandemic or endemic disease."
Britain's island status means we have a legacy of tackling potential threats. But now there is a need to deal with emerging hazards posed by chemicals or radiation.
It would have been difficult to predict last year's polonium 210 problem, resulting from the murder of the Russian agent, Alexander Litvinenko.
The consultation paper proposes a wider range of powers, such as keeping someone in quarantine - perhaps in their own home - or requiring them to report their temperature at regular intervals.
People might have to wear a face mask in certain circumstances - or a child might be told to stay away from school.
There is no question of compulsory treatment, and the proposals refer to the need to protect human rights, but the broader scope is making some people nervous.
Campaigners on HIV say the consultation evokes memories of what they say was moral panic about Aids in the 1980s.
The Terrence Higgins Trust's head of policy, Lisa Power, said: "The proposals could be used in a really wide and sweeping way.
"The way this is drafted could be taken in a lot of different directions and it's entirely up to the Secretary of state for health.
"I have been in this sector for 30 years. I have seen a lot of secretaries of state who were very good and listened to advice - but I have also seen some who I'd trust less than my cat to make health decisions."
The Department of Health denies the proposals are draconian or too vague.
A spokesman said: "This is a consultation paper and it deals with complex matters.
"One of the arguments for taking new powers is that they would enable a more proportionate response to problems.
"We want to explore the issues properly before making final decisions."
Professor Peter Taylor, from the University of London's School of Pharmacy, works on new ways of treating bacterial infections.
He said: "The powers in the consultation document seem to be extremely broad and in some ways non-specific. They do at first glance look rather sweeping.
"One example is that the legislation might be invoked relatively early, if we anticipate an outbreak of avian flu.
"It could be that people with flu-like conditions, who are harbouring a virus that isn't H5N1, could be subject to the legislation, which I don't think would be appropriate.
"But I think as long as it is backed up with a good legal procedure, there isn't much risk of things getting out of hand."
Until we can tackle the looming prospect of bird flu and other unknown hazards, officials say it is time to take a fresh and proportionate look at the public health laws.