Officers have discovered CCTV of missing man John Lord parking his car outside the Riverbank Bar at just before 3.30am on Monday 6 April 2015.
As he does so the car park is busy with several groups of people getting ready to go home from their nights out.
Temporary Sergeant Iain Blackstock said: “Were you one of them? Or do you know friends who were out in the area at the time? You may not think you have any important information but you may be able to tell us something that could help us find the 86-year-old. Please call us on 101.
“Mr Lord’s family are incredibly worried about him and we want to find him as soon as possible.”
He left his home in Woodborough Road, Alexandra Park, St Ann’s, at around 3.15am in his white Toyota Yaris and it believed he drove straight to the Victoria Embankment, where he left his car.
Mr Lord, who is described as 6ft tall, white, of a slim build with broad shoulders and grey hair, was last seen wearing dark tan trousers and a dark jacket.
If you have seen Mr Lord please contact the police immediately on 101.