The Royal British Legion (RBL) has been holding London Poppy Day today with a £1m-in-a-day fundraising goal.
More than 2,000 Armed Forces personnel, veterans and Poppy Appeal collectors were out in force across the capital to reach the RBL's target.
Actor and broadcaster Ross Kemp was encouraging Londoners to pick up a poppy today and help towards the cash goal.
Mr Kemp, an RBL ambassador, was seen rallying the troops on Horse Guards Parade alongside members of the Irish Guards and their Irish wolfhound mascot Seamus.
Mr Kemp said: "This is such a special day where Londoners get the chance to meet service personnel in person and thank them for all they do for us.
"I hope everyone will really get behind London Poppy Day and help the RBL achieve its target of raising £1m in a single day.
"The money raised will help the charity continue its vital work supporting members of the Armed Forces Community in need," he added.
Defence Secretary Ben Wallace was at Waterloo station, where he helped the cause by selling poppies.
Mr Wallace told Forces News: "I've seen an amazing effort by members of the Armed Forces today who are out here effectively raising money for tomorrow's veterans as well as today's.
Mr Wallace added: "I think that is a really great thing to see and it's always great for the public to interact with serving personnel and they can talk about their own experiences but also remind the public that the Armed Forces are here to keep them safe in these days which are a very anxious time around the world."
The Defence Secretary also said that in this remembrance period, he will be particularly thinking about "family".
"What always stands out is that we are a family. If you belong to a regiment, you start off very young and you do your service but you are always together," he said.
"I always reflect on that fact that the body of the armed forces serving and non-serving come together as one to remember the sacrifice made by many many people to allow us to live in this free country the way that we do."
Rishi Sunak, meanwhile, surprised commuters by selling poppies at Westminster underground station in central London.
The Prime Minister, who was holding a full tray of poppies, joined several Army personnel and civil servant Stephen le Roux to raise money for the RBL appeal.
Shadow Defence Secretary John Healey, alongside Shadow Veterans minister Rachel Hopkins, supported London Poppy Day at King's Cross station.
Mr Healey said it was "such a pleasure" to join the service personnel, veterans and RBL volunteers to support the event.
"Ahead of Remembrance Sunday, I urge everyone to donate to the Poppy Appeal and ensure the legion can keep doing its fantastic work," the Shadow Defence Secretary added.
Last week saw the unveiling of a huge red wall covered in paper poppies and tributes, telling the stories of those in the Armed Forces community, to mark the launch of this year's RBL Poppy Appeal.