British forces had on Friday successfully carried out one of their "most strategically significant" operations in the Afghan province where US Marines are battling the Taliban further south.
British troops launched an assault on a Taliban stronghold just north of Lashkar Gah, the capital of Helmand province, two weeks ago after dropping 350 soldiers behind enemy lines in a major airlift.
"Hundreds of soldiers from the Welsh Guards Battlegroup have successfully seized 13 key canal crossings in one of the most strategically significant British operations ever carried out in Helmand province," a statement said.
"Taking control of the crossings will now allow British troops to prevent insurgents' movements between Helmand's two largest cities, Gereskh and Lashkar Gah," said the statement from the British force in the province.
This would "ultimately improve security and freedom of movement for the local people" and was essential to allow them to participate in Afghanistan's presidential and provincial council elections on August 20.
Two British soldiers were killed in an explosion on Wednesday during the operation called "Panther's Claw".
One of them was the first commanding officer to die in operations since 1991, the British defence ministry said on Thursday.
British troops are now set to move on to secure an area north of the Lashkar Gah, the statement said.