Britain has become a more divided country after a series of political campaigns including the EU referendum have peddled fear and fanned the flames of racism, Tim Farron will warn.

The Liberal Democrats leader will also hit out at controversial government proposals to reduce the number of foreign-trained doctors and overseas students.

In a speech to the Runnymede Trust, a leftwing race-equality thinktank, he will accuse the Conservative party of letting its “reckless obsession” with migration harm Britain’s interests.

Farron will say: “The summer saw a European campaign based on fear and terror, pitching community against community. And this autumn has seen Theresa May propose moves that will make Britain a nastier, more divided and more resentful country, with attacks on foreign doctors and students as well as checks on taxi drivers.

“I dread to think what’s in store this winter.”

His comments come after the government announced a series of proposals aimed at reducing annual net migration to the tens of thousands.

The home secretary, Amber Rudd, is to consult on proposals to link student-immigration rules to the quality of colleges and courses, while the health secretary Jeremy Hunt has pledged to end NHS England’s reliance on foreign doctors by the end of the next parliament.

Another plan to name British companies that employ large numbers of foreign workers was abandoned amid widespread criticism.

Farron will hit out at the government’s stance on foreign workers, branding it “a nasty little policy that deserves to be thrown out on the rubbish heap”.

He will say the Conservatives are guilty of having a “reckless obsession with overall migration numbers, instead of standing up for what’s best for Britain.

“Liberal Democrats will fight for an open-hearted, open-minded and pro-European society. A diverse and powerful workforce is at the heart of that.”

He will also criticise the Conservative candidate for London mayor earlier this year, Zac Goldsmith, call his campaign against Labour’s Sadiq Khan “racist”, and brand the Conservatives the nasty party.