Cheap UK call access number?

[guest2]

Does anyone know of a Portuguese cheap rate UK call access number to call the UK from Portugal. For example if you call from the UK to Portugal and preceed the 00351 with 0844 8448444 you will only be charged 5p/min daytime (this is with tiscali--"SimplyDial" there is another number for evenings and weekends and you pay for the call on your normal BT bill). I am looking for the same sort of thing to use when in Portugal to call back to the UK. Preferably as the above, without any need to register or pay any seperate bill. Thanks.