Catholic aid agency CAFOD has joined calls for the immediate release of a respected British anti-corruption campaigner in Angola, arrested by armed police and charged with espionage.

Dr Sarah Wykes was charged less than one month after civil society groups worldwide appealed for greater protection for those working to end corruption.

Dr Wykes, is described by the aid agency CAFOD as “a valued colleague within the Publish What You Pay (PWYP) coalition”. She was arrested by armed police on February 18 in the oil-rich enclave of Cabinda and held in prison.

She was bailed after three days but is not allowed to leave the country, and still has not been given detailed information about the charges against her.

At the recent World Social Forum, groups working on human rights, environment, transparency and accountability in extractive industries stressed the importance of being able to continue their work free from harassment or intimidation.

Dr Wykes is a respected international campaigner working to reduce corruption in the oil and gas industries for the Global Witness organisation.

She was visiting Angola to speak to civil society, companies and the government to assess progress made on improving the transparency of money generated by Angola’s oil sector.

Alongside other members of the 300-strong international Publish What You Pay coalition, CAFOD is calling for the Angolan government to drop all charges against Dr Wykes immediately and unconditionally, and to allow her to leave Angola at once.

The safety of those who speak out on issues of transparency and corruption is a growing concern for campaigners.

The arrest of Dr Wykes follows the detention and trial of two Publish What You Pay campaigners in the oil-rich state of Congo-Brazzaville last year.