If you ask the tax office they will send you out some info, If your out of the UK so many days in a tax year (I think its over 6 months or 9 months per tax year)
Then you do not have to pay tax from on an income earned from a foriegn source, You do have to pay UK income tax on income earned in the UK (I did this for 3 years)
Be very carefull you should pay tax where you earn that income and some of the tax rates in other countries in Europe are much higher than the UK.
If you do this what ever you do keep paying you class 2 NI contributions in the UK, This will entitel you to a pention when you retire.
I live and pay my taxes in another Europeon country but still pay class 2 NI contributions in the UK.