A lawn mower, Rolex watches and a theatrical coffin are among the 150,000 items people have left on the Tube, buses and taxis this year.
Gas masks are among items left on buses, taxis and the Tube
While Londoners are most likely to lose mobile phones and books on public transport, items left behind range from the mundane to the surreal.
Three dead bats in a container, a jar of bull sperm and a £2,000 TV left in the back of a taxi are among them.
Many are returned to their owners, the rest are auctioned after three months.
Money raised goes to the running costs of the lost property office. Staff say that of "items of value", half are successfully reunited with their owners.
One in three bags is returned, one in four mobile phones and one in five books. The overall return rate is one in 12.
Items held at the lost property office at Baker Street in the past have included two human skulls in a bag, a divan bed and three World War II gas masks.
In April, it was revealed a funeral urn which turned up in the lost property office had been reunited with its guardian after five years.
The urn contained the ashes of John Ross, whose brother Peter had been carrying it in a bag which was stolen at Heathrow Airport.
TfL staff tracked him down through German words on the urn, which led them to an Austrian crematorium where they found Mr Ross's address.