British paedophiles will be targeted by a new security pact to be announced as Theresa May concludes her Africa tour in Kenya.
Downing Street said Britain will build a cyber centre in Nairobi to help Kenyan police stop child abuse images being shared online and assist efforts to identify potential victims.
The UK will also help fund work by the Kenyan authorities to access data from tech firms to catch offenders, No 10 added.
Support to police in dealing with violence against girls and women, plus legal expertise on pursuing complex terror and organised crime cases will be offered by the UK too.
Mrs May will become the first British Prime Minister since Margaret Thatcher in 1988 to visit Kenya.
She is to meet president Uhuru Kenyatta and see British soldiers who are training troops from Kenya and other African countries fighting al-Shabaab in Somalia.
Post-Brexit trade, security and overseas aid have featured in her three-day Africa visit as she made the case for the UK to seize a greater share in the market amid fierce global competition from China, France and the United States.
On the Kenyan security pact, Mrs May said: “Online child exploitation is an abhorrent crime and we are determined to ensure there is no place to hide for predators who use the internet to share images of abuse across borders, too often with impunity.
“This builds on our ongoing work with Kenya on security and criminal justice – a partnership which has already helped to convict and imprison terrorists in the UK.”
The cyber centre project is linked to Kenya’s existing anti-human trafficking and child protection unit, which involves the UK’s National Crime Agency.
This unit has helped protect around 499 children since March 2016 and helped secure convictions of British paedophiles who have sexually abused children in Kenya, Downing Street said.
Details of funding have yet to emerge.