Theresa May is to announce a tie-up with the Kenyan authorities to help track down British paedophiles as she concludes her tour of Africa.
The UK is to build a cyber centre in Nairobi to help Kenyan police stop child abuse images being shared online.
It will also assist efforts to identify potential victims and access data from tech firms to catch offenders.
Mrs May is the first British prime minister since Margaret Thatcher in 1988 to visit the country.
She is to meet president Uhuru Kenyatta and see British soldiers who are training troops from Kenya and other African countries fighting Islamist militant group al-Shabab in Somalia.
The prime minister will announce a wide-ranging new security pact between the two countries, including funding for enhanced airport security in the former British colony.
The UK will also offer support to Kenyan police in dealing with violence against girls and women, plus legal expertise on pursuing complex terror and organised crime cases.
The cyber centre project is linked to Kenya’s existing anti-human trafficking and child protection unit, which was set up in 2016 with input from the UK’s National Crime Agency.