Seen in this week's TV Choice listing for BBC2's Wonders of the Universe: 'Despite being a relatively weak force, Prof Brian Cox explores the powerful effects of gravity...' But Brian Cox fans need have no fear - this is a classic example of 'the mystery of the missing pronoun or noun', or put another way, a participial phrase at the beginning of a sentence must refer to the grammatical subject. If you miss out the pronoun or noun (which is the subject of your sentence) at the beginning, you can fall into this stylistic trap. For example, 'Being in a dilapidated condition, I was able to buy the house very cheap'. (This example is from The Elements of Style by Strunk & White).
To make perfect sense, the TV listing should read something like: 'Prof Brian Cox explores the powerful effects of gravity, which despite being a relatively weak force...'
So novice writers, please read through your work carefully and look out for stylistic traps like this.