The 10-man Foxes appeared to have earned a point when Liam Cullen struck a brilliant equaliser five minutes after John Lundstram had seen red.

But Marshall struck in the fourth minute of added time as Martin’s side suffered a fourth league defeat in 11 games.

Town almost led within three minutes as Tudor Mendel’s shot was saved by Alex McCarthy, who also denied Kasey Palmer and Nahki Wells.

Leicester went close when Kamari Doyle’s low attempt was repelled by James Shea, before Emil Riis had a goal ruled out for offside.

Luton led after 39 minutes when Jordan Clark dispossessed Caleb Okoli and teed up Wells to sweep home.

The Foxes were reduced to 10 men with five minutes left when skipper Lundstram received his second yellow card for a lunging tackle on Isaiah Jones.

Leicester thought they had rescued a point when Cullen curled home brilliantly from the edge of the box in the 90th minute.

But Town won it when Emilio Lawrence’s cross was prodded in by fellow substitute Marshall.