As a person that has never owned a GPS and relies on good old map and compass for all my walking an interesting read , I'd like to think most LDWA members are aware of the problems you can have with a compass , but always worth a reminder ! cheers for posting .

A report in online BBC news warns of magnets in devices such as mobile phones with protective cases, but also gloves and clothing fasteners, affecting compasses.

From Mountaineering Scotland:
"It [the compass] had been stored in a pocket next to a mobile phone in a case which had a magnetic closure on it, and the magnet had reversed the polarity of the compass needle, so that the north arrow pointed south. [...] more joined-up thinking is needed between outdoor clothing manufacturers and mountain users to avoid potentially life-threatening consequences. [...] The phenomenon of reversed polarity has been publicised previously in mountaineering circles."

http://www.bbc.co.uk/news/uk-scotland-highlands-islands-43063365

If you've been going in 'mountaineering circles' (Wainwright did, once) it might be your phone.

Iain