Delhi Police today booked two British "plane spotters" who were detained for allegedly recording conversations between pilots and Air Traffic Control. <br/><br/>The two were detained on February 15 night at a Hotel near the IGI airport after its staff reported to police that they were found indulging in suspicious activities.<br/><br/>Joint Commissioner of Police (Southern Range)Ajay Kashyap said, they have been charged under Telegraph Act . <br/><br/> If convicted, the duo will have to serve a prison term of up to three years, or with fine extending to up to 1,000 rupees or with both.