A top Sudanese official suspected of involvement in mass killings in Darfur province has been on a secret visit to London, the BBC has learned.
Pro-government militias in Darfur are accused of atrocities
Officials revealed Salah Abdallah Gosh, head of Sudan's national security and intelligence service, was given a visa.
He came to get medical treatment and has now left, they said.
Liberal Democrat MP Malcolm Bruce condemned the decision, saying it was inconsistent with British efforts to provide aid in Darfur.
"It just gives comfort to someone who is alleged to be responsible for what's happening there," Mr Bruce, chairman of the House of Commons select committee on international development, told the BBC's World Tonight radio programme.
Mr Gosh is said to be the third in command in the Sudanese hierarchy dealing with Darfur.
BBC world affairs correspondent Chris Morris says he also had close links with Western intelligence agencies, particularly with the US Central Intelligence Agency.
The US embassy in London declined to comment last night on whether any US officials had met Mr Gosh during his stay in London.
More than two million people have been forced from their homes and at least 180,000 have been killed in the Darfur conflict.
The rebellion started in 2003, with groups saying the region's black African population was being ignored by the central government.
Pro-government Arab militias then launched reprisals against the civilian populations.
Sudan's government has denied backing the militias and has accused Western nations, such as the US, of exaggerating the problems in Darfur for political reasons.