A police force has been lambasted by language campaigners for its use of "blindingly obvious" messages in its campaign posters.

"Don't Commit Crime" is stated on one of Hertfordshire Constabulary's posters - "All fuel must be paid for" has been added on posters at petrol stations.

Language watchdogs the Plain English Campaign said the signs were "an opposite of gobbledegook" and an insult to people's intelligence.

A spokesman said: "'Do not commit crime. Pay for fuel' is hardly a deterrent to a criminal who has every intention of driving off without paying and is merely an aggressive reminder to everyone else."

Herts police accepted that hardened criminals would most likely ignore the signs but added that it "may make someone who is nervous think twice."

The force declined to comment on the cost of the poster campaign or reveal any figures on its impact on crime.

The language campaigners said the cause of the anti-crime slogans was "a combination of branding and PR spin, combined with the obsession companies have with covering themselves."

Here are some of the notices submitted by the campaigners as examples of overly-obvious officiating:

:: Warning: Platform ends here (on the end of rail station platforms).
:: May irritate eyes (on a can of self-defence pepper spray)
:: May cause drowsiness (on sleeping tablets)
:: Caution: Water on road during rain
:: Do not open door while airborne except in emergency' (on emergency exit doors in aircraft)
:: Removing the wheel can influence the performance of the bicycle (from a Dutch bicycle manual)
:: Do not iron clothes on body (from the packaging for a steam iron)
:: For indoor or outdoor use only (!)