Worboys Antiques has dated this piece to the 1920s.
The 8 day movement has a lever platform and is marked "Mercer St Albans". (England, c. 1920)

Dimensions
15.50cm wide 22.00cm high 10.00cm deep (6.10 inches wide 8.66 inches high 3.94 inches deep)
Provenance
Thomas Mercer were Est 1858, Makers to the Admiralty.
Current Condition
The case retains its original finish in excellent condition, the movement has been serviced and is guaranteed for 12 months.
Worboys Antiques has dated this piece to the 1920s.
Established since 1978, dealing in and restoring most antiques, specialising in clocks and furniture.
You can view the stock and full dealer information on the Worboys Antiques Profile Page
Worboys Antiques is a registered member of LAPADA