Six UK politicians have called for the Bangladesh authorities to release the former prime minister, Sheikh Hasina, who was arrested on extortion charges.
In a letter to The Times newspaper in London, they said they were gravely concerned about the manner in which Sheikh Hasina was arrested.
They said she posed no conceivable security risk and should be freed on bail so she could prepare her defence.
Opposition leader Sheikh Hasina says her arrest is politically motivated.
The head of the main opposition Awami League party says she was arrested to block her from standing in future elections.
"We are... gravely concerned about the undignified arrest this week of... Sheikh Hasina," the British politicians' letter published in The Times read.
"We call upon the authorities to release her on bail so that she can prepare her defence. She has already surrendered her passport and poses no conceivable security risk or risk of attempting to evade justice," it added.
The letter is signed by MPs Anne Main, Simon Hughes and Harry Cohen, MEPs Charles Tannock and Baroness Ludford, and peer Baroness Udin.
Sheikh Hasina was arrested last week after a raid on her house in the Bangladeshi capital, Dhaka.
She faces corruption charges relating to her time in office from 1996 to 2001. She has also been accused over the killings of four political rivals.
She has denied any crime and says the arrest is a "conspiracy to expel her from politics".
The military-backed government has barred her from leaving the country.
Khaleda Zia has called for her Awami League rival's release
The arrest sparked angry protests from supporters.
The Awami League leader is the daughter of Sheikh Mujibur Rahman, who led Bangladesh to independence from Pakistan in 1971.
Her bitter rival, Bangladesh Nationalist Party leader Khaleda Zia, also faces criminal charges and has been ordered to appear before a court by 26 August over tax evasion allegations.
Last week, Ms Zia demanded the immediate release of her rival.
Correspondents say that Ms Zia's comments are highly unusual given the high level of animosity between the two former prime ministers.
Since January this year, Bangladesh has been governed by a military-backed emergency government, which has promised to root out corruption.
More than 150 prominent politicians, civil servants and businessmen have been arrested.
The government says elections will be held before the end of 2008.