Those at greater risk from flu include people with health conditions such as severe asthma, chest or heart complaints and diabetes, pregnant women and people aged over 65.
This year, the annual nasal spray flu vaccine will also be available for all children aged two, three and four years old as part of the NHS childhood vaccination programme.
The nasal spray flu vaccine is also for children aged two to 18 who are at risk from flu, such as children with long-term health conditions.
The NHS in Sutton is launching the new Flu Safe campaign this week to remind people that they should make an appointment with their GP and get a flu jab.
Dr Chris Elliott, Chief Clinical Officer of NHS Sutton Clinical Commissioning Group, said: "Flu is not like a cold – it can be a really serious illness for some people and it doesn't just affect older people. Flu can also be very unpleasant for children with some developing a high fever or complications of flu such as bronchitis, pneumonia and middle ear infection for which they may need hospital treatment.
"If you're pregnant, have lowered immunity or a long term health condition such as severe asthma, a chest or heart complaint, or diabetes, then you should also get a free flu jab from your GP and get flu safe. The flu jab is safe and it can't give you flu."
NHS Sutton CCG is encouraging everyone in the borough who knows anyone who may be at risk from flu to tell them how important it is that they get protected.
People who are carers and frontline health and social care staff are also encouraged to get a free jab to protect themselves and those around them.
The flu vaccine changes every year to fight the latest strains of flu, so even if you had a jab last winter you need another one this year to stay flu safe. The jab doesn't contain the 'live' virus so it cannot give you the flu.
Dr Elliott added: "Flu can increase the risk of developing more serious illnesses such as bronchitis and pneumonia, and can make existing conditions much worse. If you are at risk you may also be eligible for a free pneumonia vaccine, offering protection for up to 10 years. It can be given safely at the same time as your flu jab.
"If you're in any of the 'at risk' groups, the flu jab is completely free and is a safe way of protecting you and your family in a matter of minutes."
The best time to be vaccinated is at the start of the flu season from the start of October to early November, so it's good to get in early and get flu safe in time for the winter. Simply contact your GP or local pharmacist* to arrange a convenient appointment and get your jab. It's quick, safe and free for those most at risk from the virus.