ALBIE HEWITT, RIPON HOW RADIOACTIVE IS MY HOUSE? (DO I NEED TO WORRY?)

Pedantically, we could say that your house is literally bathed in radiation day and night, since visible light is radiation, and so are the infrared wavelengths coming from your radiators and the 2.4GHz frequency radio waves from your home Wi-Fi and mobile phone. But what you're probably referring to is ionising radiation - the kind powerful enough to knock electrons out of atoms and thereby cause cancer and, at very high doses, radiation poisoning and burns.

Old-fashioned cathode-ray tube monitors used to be a low-level source of ionising X-rays, but these have virtually all been replaced with flat-screen monitors, which don't emit X-rays. So the remaining domestic sources of radiation are mostly things that contain small amounts of radioactive elements. Bananas, for example, contain enough of the isotope potassium-40 that eating one gives you 0.0001 millisieverts (mSv) - roughly the same radiation dose as living within 80km (50 miles) of a nuclear power plant (in other words, virtually none).