Eight foot-tall yellow wellington boots have been placed in capital cities as part of an RNLI fundraising campaign launch.
The boots, in London, Cardiff, Dublin and Edinburgh, represent those warn by volunteers on the charity's lifeboats.
Londoner Russell Shaw is supporting the campaign after the charity saved his best friend Eddie McElligott and his dog last year.
The 75-year-old said: "I can't believe I nearly lost the two of them."
Mr Shaw's friend was walking his dog Easy along the River Thames near Chiswick in west London when it bolted after a squirrel. Mr McElligott lost his footing and fell into the water.
"He couldn't get out and became weak and hypothermic, trying to keep his head above the water. If it wasn't for the Chiswick RNLI lifeboat crew coming to rescue him and retrieving Easy, I dread to think what would have happened," he said.
Mr Shaw and his two best friends joined crew members from the RNLI's Tower lifeboat station to launch the campaign.
Celebrities including Virgin's Richard Branson, TV presenter Dermot O'Leary and five-time Olympic champion rower Steve Redgrave have put on yellow boots in support of the campaign.
Olympic sailor Ben Ainslie, radio presenters Lisa Snowdon and Dave Berry and TV presenter Fern Britton have also worn the boots in support.
