after months of preparation, borisjohnson prepares to play host to world leaders flying in for this weekend's g7 summit in carbis bay in st ives in cornwall. it's the first time the leaders have met face to face in two years. presidentjoe biden has left joint airbase andrews and will arrive in cornwall this evening. tomorrow, the prime minister, borisjohnson, will hold his first bilateral meeting with president biden. the three—day summit will officially begin on friday and last until sunday. so what's on the agenda? borisjohnson is keen for leaders to pledge their commitment to global covid vaccinations by the end of 2022. the post—covid economic recovery is high on their agenda. and pressure is growing on the leaders of the richer nations to provide more funding to deal with climate change. it's the first overseas visit for the joe biden since his election as us president. in the run—up to the summit, our north america editorjon sopel has been speaking to the us national security adviser, jake sullivan. if the administration were producing a bumper sticker for this trip, it would be "america is back".