"Before Easter (a Wandsworth officer) rang up and told me that the comprehension test would be a poem, a cartoon and a piece of factual writing about spiders. It was out of the blue. I mentioned it to one of my teachers, who said she'd already been told at an in-service training course.
"I couldn't have imagined it even on a bad day. I'm assuming the information is right. I suspect that even if you try and be totally upright, you'd be affected, even unconsciously."
Another Wandsworth head said: "I had a phone call saying 'just making you aware of the rumour that there's a possibility the tests might contain a cartoon and that the content could possibly be on spiders'.
"It places pressure on the heads. But I didn't pass the information on and it's not right to do that."
Not all schools received the leak. A third Wandsworth headteacher said: "It devalues the kids in my school who did well without the inside information. I heard the rumour and asked a colleague if it were true. I was told 'Yes, but don't tell everyone'."