Singapore said it was seeking to extradite David James Roach, suspected of robbery at Standard Chartered Bank branch in Holland Village, after he was detained by UK authorities last week.
Roach allegedly stole SS$30,000 ($22,691) from a StanChart branch in July 2016, after handing the bank teller a threatening note.
The 28-year-old fled to Thailand on the same day shortly after the crime where he was arrested. He was held at Bangkok's immigration detention centre.
Roach was deported to London on January 11 after he served a prison sentence for criminal offences in Thailand.
Singapore said it was now working with the UK authorities on his extradition, the Ministry of Home Affairs (MHA) and Attorney-General's Chambers (AGC) said in a joint statement on Monday.
"Since his arrest by the Thai authorities in July 2016, Singapore authorities have been in regular contact with the Thai authorities to secure his return to Singapore... We sought the assistance of the UK authorities to arrest Roach, with a view to his eventual extradition to Singapore," the statement said.
"We are working with the UK authorities to commence the extradition proceedings."
Reuters reported on Monday that Roach had been deported last week, but to Canada, not to Britain. The report cited a senior official in Thailand's Immigration Bureau as saying.