The surge in activism -- 58 companies ranging from beverage company Pernod Ricard to financial services company Nordea were approached in 2018, according to data from Lazard -- may translate into costly battles with brand-name firms like Elliott Management.

Only 10 percent of polled executives said they could face their foes successfully while 53 percent admit they lack a plan.

Global consulting company AlixPartners surveyed senior executives at more than 500 publicly traded companies in the United Kingdom, France, Germany and Italy in December and results show how vulnerable corporate Europe feels.

Roughly two thirds of the respondents worry about the rise of activism.

AlixPartners will release the findings on Monday.

"Activism happens quickly and it often comes from left field meaning people feel unprepared and almost ambushed by it," said Eric Benedict, UK Market Leader at AlixPartners in London.

Benedict said corporations need to look carefully at what is core and non core to their business, how to save costs, review cashflow and their capital structure and see if some can be returned to shareholders, and look at corporate governance.

"It all boils down to the 5cs," he said.

As corporations head into the traditionally busiest season for activism in the run-up to annual meetings, executives surveyed by AlixPartners said they were afraid to spend the money to prepare.

At the same time, an increase in technology, which allows investors from around the globe to easily see how companies are performing, made them more vulnerable.

"For a long time we could size the threat. We knew when and where it was coming from. Technology has changed that," said an executive polled by AlixPartners but not named to protect his company.

U.S. activists have built confidence and are no longer put off by a company's size. Daniel Loeb's $14 billion Third Point LLC has been pushing Swiss food company Nestle SA, valued at roughly $237 billion, to sell non-core units.

"The United States was seen as the wild west and executives in Europe felt they enjoyed a shroud of invulnerability. But increasingly the ways to insulate yourselves are declining,"

Benedict said.

Now more than half of the executives surveyed said they need outside help to manage activism in the next one to two years, the survey found.

(Reporting by Svea Herbst-Bayliss; Editing by Susan Thomas)

By Svea Herbst-Bayliss