Off grid: the Guardian cryptic crossword setter who wrote a puzzle while running the London marathon (4)

Guardian cryptic crossword setter Paul challenged himself to write one while he ran. Here's how he did it ... You run the London marathon, you need a gimmick. For the past 22 years I have been writing the Guardian cryptic crossword under the pseudonym Paul, after my late brother, and I had already run four marathons in his memory. I realised there are about 26 clues in a puzzle, and 26 miles to a marathon. Suddenly the idea was there, and I began to regret it immediately. I asked my crossword-se...