RSPCA London chief inspector Clare Dew said: "No-one noticed anything unusual on the bus before the monkey was discovered but we'll be looking at CCTV and logs for scanning on and off to see if we can locate the person who left her on board. This is clearly a direct result of the new legislation and is something we feared would happen. The RSPCA is urging people struggling to care for pets or unable to secure licences not to abandon their animals but to seek advice from vets or animal charities. A Transport for London spokesperson said: "We're pleased to hear that Oyster the marmoset was safely found and is now being cared for by the RSPCA. Listen to the best of BBC Radio London on Sounds and follow BBC London on Facebook, external, X, external and Instagram, external.