My 11yr old son has had mild constipation for years and is on 1 sachet of movicol per day. He poos once a day and soiling has ceased - yay! But...whenever he increases his liquid intake in summer he leaks urine a lot. Today he had soaked through his shorts in athletics club and had wet pants after cricket. He had a wee before both activities and during the cricket. He drank roughly 2l of water today (if not more). This does not happen in the winter. He is unaware of it (not sure how as it is v obvious from smell/stains). Any ideas before I go to GP please.