The suspect in the 2016 Standard Chartered Bank robbery case is planning to contest his extradition to Singapore.

David James Roach was detained by the British authorities in London on Jan 11 following a request from Singapore, a joint statement by the Attorney-General's Chambers (AGC) and the Ministry of Home Affairs (MHA) said on Monday.

"We sought the assistance of the UK authorities to arrest Roach, with a view to his eventual extradition to Singapore," said the statement. "We are working with the UK authorities to commence the extradition proceedings." Singapore has an extradition treaty with Britain.

Roach's lawyer Sundeep Pankhania told The Straits Times yesterday that his client, a Canadian national, was planning to contest the extradition, but declined to say more. His case was heard at the Westminster Magistrates' Court in London earlier yesterday.

Roach, 28, is accused of robbing Standard Chartered Bank's Holland Village branch of $30,000 on July 7, 2016. He allegedly handed the teller a note with his demands, then fled to Bangkok with the money on the same day.

He was arrested at a backpacker hostel three days later and was held in remand in Bangkok.

The Singapore authorities wrote to the Thai government, asking for assistance to send Roach back to Singapore. However, the Attorney-General's Office in Bangkok reportedly rejected Singapore's request. Singapore has no extradition treaty with Thailand.

On June 6 last year, Roach was sentenced to 14 months' jail in Thailand for violating money laundering and Customs laws by bringing loot into the country.

He was carrying the equivalent of more than US$20,000 (S$26,000) - believed to be the loot from the bank robbery - when he entered Thailand .

Roach was deported from Thailand after serving his prison term for his criminal offences there and arrived in London on Jan 11, said the AGC and MHA statement.