LONDON (AP) — Britain’s government will begin the process of leaving the European Union on March 29, starting the clock on two years in which to complete the most important negotiation for a generation. Britain’s permanent representative to the EU, Tim Barrow, informed the European Council President Donald Tusk of the timing on Monday morning, the U.K.’s Department for Exiting the European Union said in a statement. The notification of triggering Article 50 will come in the form of a letter. “We are on the threshold of the most important negotiation for this country for a generation,” Brexit secretary David Davis said.