Hague flies into a row over how much Burma has really changed

William Hague arrives in Burma this morning for the first visit by a British Foreign Secretary in more than half a century. The trip is to reward reforms by the country's government, he said.

These include the release of political prisoners and easing of restrictions on the opposition leader Aung San Suu Kyi. Further signs of reform by what was, until very recently, a pariah state will lead to the UK supporting the relaxations of sanctions by the EU and strengthening bilateral relations.

However, as the details of Mr Hague's historic journey were being announced, Ms Suu Kyi's National League for Democracy (NLD) complained that the Burmese government has freed only a fraction of the hundreds of political prisoners it is holding. Of 900 detainees released this week to mark Independence Day, only a dozen had been incarcerated for political "crimes".

Naing Naing, a senior NLD official, said: "It is true that several hundred inmates have been freed, but most of them were in jail on other criminal matters. We believe that all political prisoners should be freed, as soon as possible." Phyo Nin Thein, a lawyer whose brother, the student leader Htay Kywee, is imprisoned, added: "This does not help the country. This is mainly for ordinary criminals."

Human rights groups and foreign diplomats said that it was not even clear how many opposition activists were being held by the government, led by President Thein Sein, which succeeded the military junta. The official figure is fewer than 300, the NLD believes it is around 600, while some prisoners' support groups estimate the total to be more than 1,000. The detention centres are spread across the country, with no public access to records.

No Foreign Secretary has visited Burma, a former British colony, since Anthony Eden in 1955. The British Government maintains that continuing isolation will hamper genuine progress taking place in the country. The Burmese government is desperate to see an end to sanctions which have contributed to keeping the country one of the poorest in a region of growing affluence.

Mr Hague will meet Thein Sein and Ms Suu Kyi, as well as members of ethnic minorities who have been subjected to repression by the military junta.

"I am visiting the country to encourage the Burmese government to continue on its path of reform and to gauge what more Britain can do to support the process," he said.

"The release of some political prisoners, the dialogue with Aung San Suu Kyi, improvements in media freedoms and changes to legislation to have enabled the National League for Democracy to participate in this year's by-election are welcome reforms we urge the government to build on."

The UK is currently the largest bilateral aid donor to Burma, giving £185m over three years, channelled through humanitarian groups rather than directly to the Burmese government. The US is considering a substantial aid package following the recent visit by Secretaryof State Hillary Clinton.