THE world's largest aircraft maker has made the case for leaving the union even stronger by choosing Britain for its new European headquarters.
Boeing will be based in London regardless of the outcome of the in-out vote in June proving that membership of Europe is not as crucial to business as stay campaigners claim.
A spokesman for the company said the UK market is critical for Boeing.
Sir Michael Arthur, the president of Boeing UK & Ireland, added: "The prosperous partnership between our country and our company goes from strength to strength.
" The whole Boeing team is committed to the UK, our customers and our partners for the long-term. "
Leave campaigners said the decision is a massive vote of confidence in Britain and its ability to be the cent of global business.
Jill Seymour MEP, the UKIP transport spokesperson, said: "This is a massive vote of confidence in the UK, and shows that the referendum result will have no bearing on our importance in the world's economy in the eyes of our biggest investors."
Boeing employs around 2000 people in Britain and has invested & pound; 1.8billion.
Mrs Seymour added: "Why would the company pledge its future so confidently to Britain if there was any truth in the claims that a Brexit will wreck our economy?"
Peter Whittle, UKIP's London Mayoral added: "This is fantastic news and a great boost for London, a real vote of confidence in our great city.
"London truly is open for business and I am glad that Boeing will be making London its base for its entire European operation."
A spokesperson from Boeing said: "Today's announcement is entirely separate to the EU or Brexit debate, on which Boeing is neutral, but is about streamlining our corporate presence and the growth of the business across Europe.
" Having said that, Boeing has a long-standing relationship with the UK and it is a critical market for the company.
"New data recently confirmed that our direct employment has now surpassed 2000 - the company hired, on average, a new employee per day in 2015 - and that spending with the UK supply chain in 2015 was & pound; 1.8 billion."