Cambridge Grammar of English Hardback with cd-rom a comprehensive Guide

Last(ly) and at last

Last(ly)

, not at last, is used to label the final item or point in a list:

As a rule the multiple-function centres were the first to acquire the innovation; they

were

followed by the prefectoral towns, then by industrial towns, and lastly by those

not dominated by any single activity.

(…, then by industrial towns, and at last by those not dominated by any single activity.)

At last

is used to indicate that something happens, but later or after a longer period of

time than was hoped or expected:

By 1937 activity was 70 per cent higher than five years earlier. Much more than a 

recovery from the depression, or even a result of substituting home production for

imports, the upsurge has been interpreted as being the structural change that the 

1920s failed to achieve (Richardson 1967). New industries were 

at last replacing 

the old staples.