Lush has threatened to focus its future expansion outside the UK as Brexit sent "shockwaves" through the business.
The natural cosmetics firm said the 20 per cent of its UK workforce who do not have British citizenship "suddenly felt unwelcome and understandably upset" after the UK voted to leave the European Union.
The bath bomb maker said it will start reviewing options for growth outside of the UK, having just opened a new manufacturing facility in Germany.
"With little clarity on the government’s approach to the implementation of Brexit this remains a key uncertainty for the business going forward," Lush said in its financial statement for the year ending 30 June.
Lush has already relocated 80 employees who wanted to leave the UK to its German facility.
The cosmetics firm "flourished" due to the freedom of movement of people and goods. "Now we face uncertainty in both of these areas," it said.
The negotiation of new trade agreements could take years, but the risk is that we will be paying more import duties across the business.
With Britain close to full employment and with a severe skills shortage we are concerned that restrictions on free movement of people will impact the availability of both the skilled and the unskilled restricting future growth in both our UK manufacturing and buying facilities.
Lush announced a focus "to look after and invest in" its staff this year. It said it implemented the living wage for all UK permanent staff, doubled maternity pay benefits and worked to set up an employee benefit trust.