The man, said by police to be from London, was arrested in a busy street in Brighton at around 4.15pm yesterday.
Officers from Sussex police made the arrest following a tip received as a result of a televised appeal on the BBC programme Crimewatch, which was broadcast on Tuesday.
The man, who has not been named, was waiting last night for Metropolitan Police detectives who plan to take him back to London for questioning.
The arrest follows earlier police appeals for help in tracing Miss Stacey's colleague, Steven Reid, 33. Police described Mr Reid. a psychology researcher, as "a significant witness".Reuse content