I spotted the crossed grain symbol on a website yesterday (see blog about said company tomorrow) and it made me realise that it's quite rare to see the symbol and wonder what the criteria are to use it.
I found the answer on the Coeliac UK website .
It indicates "when a food has less than 20 parts per million (ppm) of gluten so it is safe for people with coeliac disease to eat."
They "registered the Crossed Grain symbol as a trademark across Europe and also own the worldwide copyright. The symbol can only be used under licence by companies and organisations on food and drink products which meet (their) criteria, and in certain publications after approval."
There is a charge to use the symbol but I hope that doesn't put anyone off, I'd love to see it used more often.
For more information on food labelling for Coeliacs see this page on the Coeliac UK website.