Mr Shinawatra and his wife Potjaman have had their British visas revoked
The British government has revoked the visas of the former Thai prime minister Thaksin Shinawatra and his wife.
An e-mail sent to airlines from the British embassy in Bangkok told them not to allow the couple to board flights to Britain.
Mr Thaksin was deposed in a military coup in 2006, and travelled to Britain.
He has since been convicted by a Thai court on corruption charges and sentenced in absentia to two years. His wife faces three years for tax evasion.
A Thai foreign ministry official told the Reuters news agency: "The foreign ministry has checked the reports with British authorities and they have confirmed that the visas were revoked."
But Mr Thaksin's spokesman, Phongthep Thepkanjana, said: "I spoke with Thaksin's secretary and he said that Thaksin still had not been notified by the British government."
The Home Office and the British Embassy in Bangkok said they would not comment on individual cases.
Mr Thaksin is thought to be travelling in East Asia - a week ago he made a telephone address to more than 60,000 supporters packed into a Bangkok sports stadium.
For much of the past two years Mr Thaksin and his family have lived in the UK.
He has not only invested in expensive properties here but also bought Manchester City Football Club, which he sold in August.
Following the withdrawal of their visas Mr Thaksin and his wife will now be forced to find a new home.
The cases against Mr Thaksin include corruption charges related to the purchase of state land by his wife, abuses of power over government money, concealing assets and tax evasion.
The former leader retains a lot of support in rural areas of Thailand, but also has many detractors who would like nothing more than to see him in jail.