In message , at 13:23:46 on Sat, 2 Apr 2016,
" remarked:
Waitrose has announced that it will be the first supermarket to launch
on the TfL network by taking over a disused station on the Piccadilly
line.

The concourse at Down Street station will be redeveloped to create a
unique retail space for TfL customers.

Joking apart, I remember when there were shops (well, kiosks) on the
platform at several UndergrounD stations.

There still are - Embankment, Monument and Hammersmith come to mind
immediately.

The kiosks at Monument aren't behind the line, however, whereas the two
at Embankment on the District line are.

For the avoidance of doubt, I'm only interested in kiosks on platforms,
"airside" of the ticket barriers.
--
Roland Perry