Four more people in London have died after contracting swine flu, including a baby less than six months old.
The other casualties are a 70-year-old man, a 39-year-old woman and another adult. All of the victims had underlying health problems.
Three other possible swine flu deaths are also being investigated.
NHS London said the latest fatalities, which happened in the past two weeks, bring the total number of swine flu-related deaths in the capital to 10.
The baby died at Royal Free Hospital last week.
Dr Simon Tanner, regional director of public health at NHS London, said: "We would like to extend our deepest sympathies to each of the families affected at this very difficult time.
"It is also important that these deaths be kept in perspective.
"All four had underlying health conditions and these upsetting cases should be kept in context with the many people who have had swine flu and recovered just a few days after experiencing a mild illness."
Andy Wapling, head of emergency preparedness at NHS London, said: "We would like to reassure people that NHS London is well-prepared - all NHS organisations have plans which have been practised and checked regularly.
"NHS London has put in place recently audited plans on how to prepare for flu pandemic and ensure that anyone who needs help will receive it."
Twenty-nine people have now died in the UK after contracting swine flu and the number of new cases hit 55,000 last week.
The NHS has seen a surge in calls and consultations.
Ministers in England have responded by promising the National Flu Service will go live at the end of next week to relieve pressure on hospitals and GPs.
The government has also warned that deaths from swine flu this winter could be between 19,000 and 65,000 in the UK.