London (CNN Business) A messy political fight between Switzerland and Europe is creating headaches for regional investors and showing Britain what life could be like after Brexit.

Swiss regulators on Monday barred the trading of Swiss stocks in the European Union after negotiations stalled on the future relationship between the wealthy Alpine country and the world's richest trading bloc.

shares of companies including Novartis NVS Nestle NSRGF Roche RHHBF That means investors, at least in the near term, will struggle to tradeshares of companies includingandon venues such as the London Stock Exchange and CBOE Europe, which is also based the major financial capital.

And it's an omen of what could be in store for the United Kingdom on a much bigger scale and with much more at stake if it departs the European Union in October without a deal to protect trade in goods and services.

"They clearly want to send a message [to Britain] about access to the European market," said Karel Lannoo, chief executive at the Centre for European Policy Studies, a think tank in Brussels.

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