Make UK 0800 numbers free from your mobile phones?

[Tarquin Farquart]

Here in the UK numbers with an area code of 0800 are free to dial, unless you are dialling from a mobile phone in which case you will be charged for the call.

There is a rumour going around that if you drop the inital 0 (i.e. the number starts 800 etc.) the call will be free.

The Wikipedia page on toll-free numbers mentions this, but there is a "citation needed".

In the UK, numbers starting "0500", "0800" or "0808" are free, with "0800" the most commonly encountered. The range 0808 1570xxx is set aside for fictitious uses in TV and radio. Additionally, numbers in the range 0808 80xxxxx are reserved for not-for-profit helplines. Since Orange UK introduced charges for dialing freephone numbers in December 2005, all British mobile networks now charge for calls to freephone numbers, with certain limited exemptions (notably Childline). From some mobile networks, certain freephone numbers such as vehicle recovery services may remain free to the user by omitting the leading 0.

Has anyone heard of this rumour?