I have been asked to reply.
Earnings data at the parliamentary constituency level are not available.
However, earnings data are available by Government office region. Although it is not possible to estimate the number of jobs paid exactly at the National Minimum Wage, the DTI estimates that in April 2005 there were 28,000 jobs held by employees aged 16 or over in the London region paid a wage within a 5p range of the National Minimum Wage. This estimate is based on data from the Office for National Statistics Annual Survey of Hours and Earnings 2005.