Three UK diplomats have been evicted from a hotel meeting in Eldoret in Kenya's Rift Valley by a local politician for "violating protocol".
They were also suspected of interfering in the International Criminal Court cases of Kenya's leaders at The Hague.
Eldoret is the home of Deputy President William Ruto, who has denied charges of crimes against humanity.
The UK says their High Commission officials were in the area to discuss a sports event to promote peace.
The charges against Mr Ruto and President Uhuru Kenyatta relate to violence following the disputed 2007 election, which left some 1,200 people dead.
The BBC's David Okwembah in the capital, Nairobi, says diplomatic relations between Kenya and the UK are at an all-time low because of the ICC cases.
Last week, the UN Security Council rejected an attempt to suspend the trials at the ICC for a year.
The resolution fell short of two votes needed to pass it, with the UK, US and France abstaining.
Daniel Chemno, the deputy governor of Uasin Gishu county, stormed into a meeting on Thursday at a hotel in Eldoret where the British officials were meeting civil society groups.
"How can you come here without having the courtesy of notifying the county government of your presence and purpose of your visit as diplomatic protocol demands?" he said.
Their presence had raised suspicion that they were on a mission to collect new evidence and recruit additional witnesses to testify at The Hague, he added.
The UK foreign office said in a statement that the British High Commission had informed the Ministry of Foreign Affairs of the visit prior to travelling, and had separately sought to arrange a meeting with the governor's office.
"The officials later met the deputy governor and separately members of the county assembly," the statement said.
The officials also met a "range of individuals and organisations involved in efforts to build peaceful relations between different communities in the region, including a council of elders, church leaders and peace activists".
"The UK is a proud partner of Uasin Gishu and Kenya, and has a long history of partnership that we wish to develop even further."
This week at an annual meeting of ICC member states, there has been a discussion about whether the treaty setting up the court should be changed to allow heads of states immunity from prosecution, prompted by Kenyan and the African Union.
The ICC trial of Mr Kenyatta, who denies the charges he faces, is due to start in February.
European diplomats wrote a letter printed in Kenyan papers earlier this week raising concern that several ambassadors - including those from France, Germany and Italy - have been waiting for months to present their credentials to President Kenyatta.
State House has blamed this on the president's "busy schedule" and not a snub linked to the ICC.