how can i disable my alarm on my w reg ford mondeo?

having problem with my w reg mondeo alarm system, whenever i lock my doors my alarm will go off, disconnect the horn part of the system by removing the feed to it, but the lights flashing are causing my battery to run flat, so leaving my door unlocked at the moment to removed the problem which is obviously not a great solution, just wondering if there is anyway i can disable the whole alarm system while i save the funds to get it fixed properly. any ideas? thanks