PML(N) Chief Nawaz Sharif Saturday said the rift between his party and Pakistan People's Party is deepening with time and refused to comment on the statements of Governor Punjab Salman Taseer. While talking to a private TV channel correspondent, while travelling in a plane, he said he was heading to London on a five-day private tour for medical check-up of his son. Nawaz said if PPP failed to honour its promises and agreements the rift between the two parties will keep growing deeper. Replying to a question regarding possibility of his meeting with PML-Q leader Ch Shujaat who is already in London, Nawaz said such possibility does not exist.