Thousands of Iraqi migrants who arrived in the UK on small boats face being deported under a new returns agreement.
Prime Minister Sir Keir Starmer will host Iraqi PM Mohammed Shia' Al Sudani for talks in Downing Street on Tuesday.
And the two leaders will begin talks on a returns agreement to "help dismantle the people smugglers' business model".
The UK has struggled to return illegal migrants to Iraq despite them being among the highest of the nationalities of small boat arrivals.
More than 2,000 Iraqis crossed the Channel in the year to September. But less than 30 were deported.
Prime Minister Sir Keir Starmer said: "Today marks a new era in UK-Iraq cooperation, which will deliver mutual benefits from trade to defence, as we continue to work together towards stability in the wider region.
"It's clear that Iraq shares our priority of delivering economic growth and the £12.3 billion export package being unveiled today offers huge opportunities for British businesses, representing a step-change in the trade and investment relationship between our two countries.
"Secure borders are a vital foundation of our Plan for Change, so I am also very pleased to get started on talks for a bespoke returns agreement between our countries.
"The deal will help dismantle the people smugglers' business model by sending the clear message that if you come here illegally, you cannot expect to stay."
Home Secretary Yvette Cooper secured the commitment for a returns agreement during a visit in November.
Under the deal, Iraq has vowed to take back more failed asylum seekers.
Baghdad has committed to helping more deportations by providing more identity documents for suspected Iraqi nationals.
Britain will also pay Iraq to boost its capacity for dealing with migrants returning to the country as well as for programmes to help returnees reintegrate into society.
But Shadow Home Secretary Chris Philp said:
"Since the general election, the number of illegal immigrants who have arrived by small boat has increased by 29 per cent. This is because the Labour Government scrapped the deterrent the National Crime Agency said we needed before it even started.
"The Labour Government are also failing to mention that returns of people who have crossed the Channel by small boat amounted to under 5% of the arrivals from July to September and small boat returns were actually lower than the period before the election under the previous Conservative Government.
"The asylum backlog is up 13% under Labour - despite the fact they promised to reduce it. And there are over 6,000 more asylum seekers, who typically entered the country illegally, in hotels under Labour, showing they have broken their commitment to the British people to end hotel use."
The Daily Express in August revealed how more British officers and intelligence specialists will be based in Iraq to snare smuggling kingpins.
The Home Office wants to "go after" the criminal networks "at source" and lead international operations.
Iraqi-Kurdish smuggling gangs control most of the beaches and camps in Northern France, it is understood, meaning officials want to ramp up National Crime Agency operations in the smugglers' home towns.
Iraqi-Kurdish gangs control migrant smuggling operations from Calais to Dunkirk, this newspaper understands, with territory split up according to where the criminals are from, such as Erbil, Sulaimaniya, Ranya and Sharazoor.
Criminals from Ranya are said to control a large part of the territory between Calais and Dunkirk.
Home Secretary Yvette Cooper said: "When I signed the landmark deal with Iraq in November, it was a clear signal of our commitment to dismantle the criminal smuggling gangs together.
"Our world-first security agreement with Iraq is already showing its impact. By strengthening border security with our Border Security Command, enhancing intelligence-sharing, and providing additional funding to support Iraq's law enforcement capabilities, we're targeting people smuggling gangs where it hurts.
"Today is the next step in ensuring this important partnership with Iraq goes from strength to strength.
"As a result, we are making it harder for criminals to exploit vulnerable people, and ultimately we are bringing them to justice."
Dozens of migrants were detected crossing the Channel on Monday.
On Saturday morning, a Syrian migrant was declared dead after being reportedly crushed to death on a floundering inflatable vessel just off the coast of France.
A 33-year-old man, also of Syrian heritage, has been arrested, according to French authorities.
According to official figures, both boats intercepted by British authorities so far this month were carrying more than 60 people.
A total of 36,816 migrants made the crossing in 2024 - the second highest annual total since records began with the average number of passengers on each boat making the crossing was 53.