Happy summit day, one and all. Today is the new Labour government’s first big business bash, as proceedings kick off at the Guildhall. Ministers are insisting that Britain is open for investment (honest, guv) ahead of Rachel Reeves’ Budget on 30 October. Yet while there were some early positive signs for the Prime Minister – with five of the world’s biggest banks signing a statement of support today – there seems to be a fly in the ointment in the form of one man’s absence.