Chief of the British pharmaceuticals giant AstraZeneca (LON:AZN) has said a three-year Brexit transition period should be implemented, with more clarity on long-term effects.

Speaking to the Swedish newspaper, Dagens Nyheter, said that very early into the transition period “we need to know what to expect in years four, five and six,”

British Finance Minister Philip Hammond admitted to the uncertainty surrounding Brexit hurting businesses told BBC radio on Monday that the two-year transition period would help. 

This is the first time that AstraZeneca has expressed criticism over the Brexit process.

The company boss did, however, refuse to sign the government’s letter asking FTSE 100 businesses to back the Brexit strategy.

“We all share an understanding that Brexit is happening, a commitment to ensure that we make a success of the outcome for the whole country, and a confidence that a global Britain has the potential to become one of the most productive economies of the 21st century,” it said in the letter.

Pascal Soriot did not sign the letter due to the uncertainty and lack of progress surrounding the Brexit process.

Labour MP Ben Bradshaw said the leak of the letter was a sign of businesses opposing the hard Brexit plan.

“Just today, businesses in sectors ranging from farming to hospitality have reacted with fury to the government’s leaked plans to damage our economy by carrying out a draconian crackdown on immigration from the EU,” he said.

“And UK businesses have been clear that they value our trade links with the European Union, and that leaving the single market and customs union will risk damaging our economy.

“If the government wants a better reception from British business, they should end their hard Brexit rhetoric and focus on maintaining the economic benefits of EU membership as they have promised.”

In responce to the link, a spokesperson from Number 10 said: “Business has an important voice in the conversation taking place over Brexit and we will continue to listen to them. One of our aims is to make sure we deliver a Brexit that is as smooth as possible for business.”