Most of Spain is 220 volts, so any British-bought laptop will be OK. Some remote parts may have 110 volts so a transformer would be needed. Be aware some buildings may have both! The phone system should be OK.
As noted above, power is no problem. You should still need a plug adaptor (that's just for the plug, the voltage is no problem).
If you are going to use a modem to connect to a telephone line for your internet connection, you will aslo need a telephone outlet adaptor. Spain uses the RJ11 (the USA one) which is different from England. Just minor details.
If there's more information you need about using computers in Spain, DieSse is the one to ask. He works on computers in Spain.