Is there a decent spirit level app for my iphone because I work in the building trade and am constantly misplacing my physical spirit level in times of need?

Your iphone actually has a built-in spirit level app, although you would be forgiven for overlooking it as it is well hidden. Simply locate and launch your Compass app (which is usually tucked away in the ‘Extras’ folder) and then swipe to the left when the compass interface appears.

You should now notice an unfamiliar ‘level’ interface. Remember, it flashes red for bad angles and green for good ones!