“Enough is enough. We are all running out of patience,” Juergen Maier, the CEO of Siemens (SIEGY) UK, told lawmakers in an open letter published Monday in Politico.Maier said that continued uncertainty over Brexit has made it difficult to invest in the United Kingdom, where the global engineering giant employs 15,000 people and generates annual sales of roughly £5 billion ($6.6 billion).The CEO said in the letter that he can “no longer defend” the actions of parliament to his board, “making it hard to win support for finely balanced investment decisions” that affect UK jobs and competitiveness. UK lawmakers will vote Monday on alternatives to Prime Minister Theresa May’s divorce deal, which they have rejected three times. The exit deadline — delayed once already — is less than two weeks away.If politicians are not able to unite around an alternative plan, and if the exit process is not delayed for a second time, Britain risks crashing out of the European Union on April 12 without a transition that protects trade.A messy departure would result in new tariffs, red tape and other barriers to trade that would be hugely damaging to many companies. The UK government has warned that a disorderly break would cause the economy to slump into recession. The Bank of England said fallout from the most disorderly scenario would be worse than the financial crisis.”People’s livelihoods are at stake, and our reputation as a country for stable and sound business investments could be in tatters by the end of the week if you fail,” said Maier.The concerns voiced by Maier are shared by companies across the United Kingdom. Some have already diverted investments because of the continued uncertainty. The Bank of England says Brexit is costing the UK economy £800 million ($1 billion) a week as the uncertainty causes investment to drop and forces consumers to tighten their belts.The Society of Motor Manufacturers and Traders said last week that the number of cars produced in Britain plunged over 15% in February compared to last year, the ninth consecutive monthly decline.Nissan (NSANF) has cited Brexit as one reason why it scrapped plans to build its new X-Trail SUV at its factory in the English city of Sunderland. The Bank of England said the UK economy is now 2% smaller than it would have been if the country voted against Brexit in the 2016 referendum, chiefly because of the Brexit uncertainty.