A new website advising farmers how to prevent potentially-explosive fertiliser from falling into the hands of terrorists has been launched.
Agricultural fertiliser has been used in a wide-range of terror attacks including bombs at Docklands in 1996, Omagh in 1998 and the Real IRA campaign in mainland Britain in 2001.
Las month's train bombings in Mumbai, India, also used ammonium nitrate from fertiliser, killing more than 200 people.
Now the National Counter Terrorism Security Office - the police agency which works with MI5 on anti-terror measures - has joined forces with the National Farmers' Union to offer advice.
The site says: "Regardless of how much fertiliser you store, it is important that you consider measures to prevent it from being acquired and misused by criminals.
"The vast majority of terrorist attacks in the UK have used home-made explosives, most of which has been fertiliser-based."
It suggests stepping up security around areas where fertiliser is kept.