The answer is simple Colonel.
Don't have:
any property owned or rented.
a credit card, debit card, loyalty card, driver's licence, passport, bank or other account.
taxable income - so the tax man misses you.
any vehicle.
Don't:
draw any pensions, private or NHI.
get injured or visit a doctor.
be at home on census night or any anyone else's home.
travel anywhere out of England.
As to census night, I suspect you could be safe in prison as prisoners may not have a vote though am uncertain on this. But then, officialdom would know you were there which ruins that idea I guess.
That computer is also a problem.
Siberia perhaps?