The British authorities refused to comment on whether they have frozen any assets owned by former Yemeni president Ali Abdallah Saleh and two leaders of the Houthi rebels.

On 18 December, the EU Council decided to impose financial sanctions, including asset freezes, on Saleh, the president of Yemen’s General People’s Congress Party Abd Al-Khaliq Al-Houthi, and the Houthi group's second-in-command Yahya Abdullah Al-Hakim.

The council blacklisted Saleh for obstructing peace in Yemen, notably for backing the Shiite Houthi militia that has seized power in Sanaa.

The British Treasury said it is unable to publicly release information about specific assets frozen in the UK or EU belonging to particular individuals for legal reasons.

These reasons include “restrictions imposed by EU and domestic law, both under sanctions and data protection legislation, as well as for reasons of confidentiality,” a spokesman for the Treasury told Ahram Online.

"We have a strict policy of not discussing individual sanction designations in terms of the individuals who are designated or the amounts of money concerned,” he added.

In November last year, the 15-member United National Security Council, which includes the UK, imposed sanctions including an assets freeze on Saleh, who was forced out of power in 2012 under a Gulf state-sponsored initiative.

The UK Treasury has warned financial organizations that failure to comply with financial sanctions legislation or seeking to circumvent its provisions is a criminal offence.

The Treasury is responsible for informing and notifying financial institutions about the effects of asset freezes and sanctions.

In a financial sanctions notice, the Treasury's Asset Freezing Unit also advised them to report any findings to the Treasury, together with any additional information that would facilitate compliance with the regulation.

The UK is one of at least 20 countries which are believed to host billions of dollars in assets amassed by Saleh during and after his 33 years in power.