LONDON (Reuters) - One in seven businesses from European Union countries with a presence in Britain have moved parts of their business out of the country because of concerns about disruption after Brexit, according to a survey published on Tuesday.

Fourteen percent of EU firms with assets in Britain, such as offices, warehouses or factories, have scaling back their business, the survey by the Chartered Institute of Procurement and Supply (CIPS) showed.

Furthermore, 11 percent of EU companies had moved some of their workforce out of the United Kingdom since the Brexit vote in 2016, the survey of supply chain managers showed.

The survey was conducted before Monday's announcement of a 21-month transition deal that will leave Britain's access to EU markets unchanged until the end of 2020.

But John Glen, an economist with CIPS, said companies were more worried about the lack of clarity about the long-term relationship between Britain and the EU.

"There comes a moment when companies need to put contingency plans into place," Glen said. "We need to start getting real about what will actually happen."

The survey also showed that almost one in four British firms with suppliers in the EU was having difficulties in securing contracts that run beyond Britain's scheduled departure from the EU in March 2019.

In response, a third of British supply chain managers with EU suppliers said they were already looking for alternative suppliers inside the United Kingdom.

CIPS said nearly a third of respondents had raised their prices because of the impact of Brexit, which caused the value of the pound to fall, pushing up the cost of imported goods.

"Businesses have little choice but to pass on some of their rising costs to consumers in order to protect their profit margins," Glen said.

CIPS surveyed a total of 2,418 supply chain managers in two rounds of questions between Feb. 6 and 19 and March 5 and 13. Respondents came from a range of sectors including manufacturing, financial services, retail and construction.

(Writing by William Schomberg, editing by Andy Bruce)