"The CTU was turned into an effective force because [former Yemeni President Ali Abdullah] Saleh wanted to have a competent strike force. However, it never fully fulfilled the role that the US and UK intended," the report published on Monday read.
According to the report, the United States and the United Kingdom set up a joint training team to back the newly formed CTU. However, relations between the US and UK sides were not always smooth, and the group was eventually split.
In 2006, the United Kingdom began changing the strategy, first by appointing Captain Philip Holihead as defense attache. It then introduced the Maritime Training and Advisory Team (MTAT), made up of permanent trainers, and the Counterterrorism Training and Advisory Team to help train the Coast Guard and the CTU, respectively.
"The UK training team had sustained access to the unit from 2006-2011. Over that period the unit became highly proficient, gained significant combat experience, and perceived itself as an elite force," the report read.
However, the functioning of the unit faced several problems.
"Relations between the Yemeni government and tribal groups did not facilitate access, and poor coordination with intelligence services made it hard to plan operations," the report said.
The study was prepared by journalist and historian Jack Watling, and investigative reporter and producer Namir Shabibi. The authors said they had interviewed dozens of Yemeni, US and UK sources, among others, involved in counterterrorism operations between 2014 and 2015 in Yemen.
Yemen has been torn apart by an armed conflict between the government forces of President Abd Rabbuh Mansur Hadi and the Houthi movement. The Saudi-led coalition of mostly Persian Gulf nations has been carrying out airstrikes against the Houthis at Hadi's request since March 2015. The country has experienced a dire humanitarian situation, with all efforts to end hostilities unsuccessful so far.