A group of Kenyan MPs have said they will table a motion in parliament for British farmers to be ejected from the khat-growing Meru region.
They are angry about moves by the British government to ban the use of the leafy substance from this July.
Last year, the UK government decided - against some expert advice - to treat khat as a class C drug to "protect vulnerable members of our communities".
It is traditionally used by Ethiopian, Kenyan, Somali and Yemeni communities.
The mildly narcotic leaf - a herbal stimulant - is already banned in most of Europe and in a number of other countries, including the US and Canada.
'Fighting for rights'
The MPs say that the British move will force almost two million people out of jobs in Meru, which is one of Kenya's 47 counties and lies to the north-east of Mt Kenya.
It is not clear how many British nationals own farms in Meru.
But the MPs say they have about a quarter of the farmland in Meru, including wheat and barley farms.
Florence Kajuju, one of the MPs behind the motion, said the government had the right to compulsorily buy property for later public use.
The arable land in Meru owned by UK farmers should be made available to locals as areas used to grow khat could not be used for other crops, she said.
"If they cannot allow us to access their market then they should also then be willing to let go of tracts of land that could be occupied by the Meru people," Ms Kajuju told the BBC.
She said Kenyans were used to fighting for their rights as they had had to do so to gain independence from Britain.
Correspondents say even if the motion was passed by MPs it is unlikely the government would implement it given its policy of accommodating foreign investors.
Effects and risks of khat
- Users feel more alert, happy and talkative. It suppresses the appetite
- Heavy use can lead to insomnia, high blood pressure, heart problems and impotence
- Longer-term risk of developing mouth cancers
- Can create feelings of anxiety and aggression, and cause paranoid and psychotic reactions
- Can make pre-existing mental health problems worse
Ms Kajuju travelled to the UK last year to appeal for the ban not to be enforced, saying it was important that the British government was not duped by a misinformation campaign.
Khat was not only of economic importance but of cultural significance to many Africans, she said.
Last year, the UK's Advisory Council on the Misuse of Drugs (ACMD) said there was "insufficient evidence" that khat caused health problems although regular users suffered withdrawal symptoms.
It also said that there was also "no evidence" that khat, made from leaves and shoots of a shrub cultivated in the Horn of Africa and the Arabian Peninsula, was directly linked with serious or organised crime.
But the UK's Home Office minister warned that failing to ban the drug could lead to the UK becoming a khat trafficking hub.