While some mobile operators currently charge up to 40p per minute for calls to 0800, 0808 and 0500 numbers, calls to these numbers have always been, and will remain, free when called from a giffgaff SIM card.
On 12 December 2013, Ofcom announced that 0800 and 0808 numbers will become free to call from all landline and mobile networks on 26 June 2015. However, this change does NOT apply to calls made to 0500 numbers. Mobile networks will be allowed to continue charging for these calls.
On 3 June 2014, Ofcom announced that the 0500 range of numbers will be closed on 3 June 2017. All users of these numbers have been offered the matching 0808 5 number as a replacement, e.g. 0500 112233 becomes 0808 511 2233.
Of the one million possible six-digit numbers found within the 0500 prefix, many thousands of numbers are currently active and in service. They are used by the BBC, various home shopping catalogues, several banks and insurance companies, a variety of well-known retailers, several travel companies and a selection of colleges and universities.
If they wish for their customers to be able to call them free of charge on their mobile phones from 26 June 2015, they will need to change their number by that date. While many organisations are expected to make the change from 0500 to 0808 5, not all will choose to do so. Some may already have other 0800 and 0808 numbers reserved or in service that they will wish to use. Others may decide to activate a new 03 number instead. In all cases, if they fail to change their number away from 0500 by 3 June 2017, they will lose it.
If you have any 0500 numbers in your list of contacts, make sure you check the respective organisation's official website for details of any forthcoming number changes. It may be worth making a quick call to any such 0500 number just in case there is already a recorded announcement on the line with details of what's happening.
If you're speaking to an organisation that currently uses an 0500 number and they have no idea about the forthcoming changes, point them in the direction of this THE END OF 084 AND 087 NUMBERS FOR CALLING BANKS AND INSURANCE COMPANIES