The UK foreign secretary William Hague is "playing an avoidance game" over the case of Bradley Manning, the US soldier accused of downloading and leaking classified cables to WikiLeaks, according to Ann Clwyd, a Labour MP.
The former human rights envoy to Iraq has also accused the Foreign Office of "continued stonewalling" of Manning's mother, Susan.
The charges against Manning include "aiding the enemy" – a capital crime.
Manning's mother (who is British) wrote to the foreign secretary three weeks ago, asking British consular officials to visit her son in military prison to check on his physical and mental health, which she said was deteriorating.
At the time she wrote her letter, Manning, 23, had been in custody since last May in conditions that provoked widespread criticism of the US military and government. He was being held in solitary confinement and on suicide watch, which required him to be stripped to just a smock at night and checked on repeatedly.