Daily Mail Crossword Friday

[suechu]

Morning all and a happy Friday from snowy Northampton

Help pse with 13a Figurative expression left over at end of lecture (5)

Must be trope obviously, but can't see where it comes from in the clue?

Thank you kindly

[Calibax]

PORT(left) reversed + (lectur)E

[bibblebub]

left over = 'port' backwards = TROP, end of lecturE = E

[wrongtupelo]

Left is the port side, turned over (trop). End of lecture is 'e'.

[suechu]

Thanks to all, my brain is obviously not lateral enough!