Britain and Iraq sought to develop new areas of co-operation as Prime Minister Mustafa Al Kadhimi met Boris Johnson in Downing Street on Thursday.
The one-hour meeting reflected on the success of the campaign against ISIS, and how to strengthen the historic ties between Baghdad and London.
"We're delighted to welcome Prime Minister Al Kadhimi today to recognise the strong friendship that exists between Iraq and the UK," Mr Johnson said.
"The prime minister should know that our government here in the UK is right behind him."
Mr Al Kadhimi added his own remarks on the bilateral relations: "I am grateful for all the support offered by the UK to Iraq, including its role in defeating ISIS.
"This support means Iraq and Britain enjoy strong relations as friends and allies."
The visit to London is the last leg of Mr Al Kadhimi's European tour, in which he met Chancellor Angela Merkel, German parliamentarians and business leaders.
Before Berlin, he travelled to Paris where he met French President Emmanuel Macron.
Mr Al Kadhimi later said that the visit represented an important opportunity to establish economic and security co-operation with the powerful economies of Europe.
In all three capitals, the threat from ISIS remained a shared concern.
“ISIS is still a challenge for the region and they have established an identity everywhere,” Mr Al Kadhimi said.
"The Paris incident last week is proof of that and I offered my condolences for that act."
The British exit from the EU has given fresh impetus to Iraqi efforts to improve bilateral ties.
“Britain has a special importance especially after Brexit,” Mr Al Kadhimi said.
“We are seeking a special relationship that complements the relationship we have with other European countries.”
In a statement from Downing Street, Mr Johnson pledged support for the security challenges faced by Iraq and the reform programme that Mr Al Kadhimi has initiated.
“The leaders agreed to work together to address critical political, security and prosperity issues, and the prime minister pledged the UK’s support for the Iraqi government as it implements reforms,” the statement said.
“They also welcomed the first meeting of the Iraq Economic Contact Group today in London, which will help to drive forward efforts to address the challenges faced by Iraq and create opportunities for the Iraqi people.”
Mr Al Kadhimi said he was confident that Iraq’s relationship with the US could be put on a stable footing after next month’s presidential election.
“Everyone is seeking an opportunity for dialogue,” he said. “We are seeking an opportunity to go beyond this sensitive issue and its implications, whoever is in the White House.”
Mr Al Kadhimi's accompanying delegation also met think tanks and was involved in key business talks during the visit.
Fuad Hussein, Iraq’s Foreign Minister, and Minister of Defence Jouma Al Juburi held meetings with their British counterparts during the two-day visit.
On his appointment and promises to lead a reforming government, Mr Al Kadhimi compared the challenge with crossing a tightrope between tall buildings on a bicycle.
"If I might add one more metaphor, I dance on a daily basis with snakes but I am looking for a flute to control them," he said.
In the "Iranian-American" conflict, Mr Al Kadhimi made clear his determination to steer clear of the traps in his path.
"Some people are expecting this government to enter into a confrontation with others but our aim is to reduce to zero the problems facing the people," he said.
That means restoring the state's monopoly on weapons, and he spoke forcefully about working with allies to end the threats posed by factions in control of armed groups.
"Any weapons outside the control of the state is not allowed," he said. "At the end of the day the country has to establish a monopoly on the use of arms."
Mr Al Kadhimi repeated his determination to hold early elections by June 6 to reset the Iraqi political scene.
An electoral law bill is making its way through the legislative process to ensure a "fair and secure" vote would raise "Iraqi citizens faith in free elections".
"The sixth of June is an indisputable date."