BBC Academy – Journalism – Grammar, spelling and punctuation
I must admit I mistakenly use ‘less’ far too often. BBC’s style guide:
Use ‘fewer’ when you can count something, as in The committee wants to have fewer meetings next year. If you cannot count it, use ‘less’, as in Voters are calling for less bureaucracy. The same rule applies for percentages: hence, you would be correct to say Less than 30% of the hospital survived the fire and Fewer than 30% of the patients were rescued.
Do not use ‘no less than’ with numbers – say eg: He attacked her on no fewer than 12 occasions.
However, ages, heights and weights take ‘less’ eg: Tom Thumb was less than 3ft (91cm) tall; Police say the man is less than 30 years old; She weighs less than seven stone (44.5kg).