Security of Ex Government Prime Ministers & Cabinet Members

When these people have left government / retired then they should be afforded security  whilst they reside in the UK or on vacation.

However, once they embark on a career (as has Mr T Blair) then their security should end at the departure gate of the airport.

Security should then be provided by the country that these persons visit for promoting their own business ventures.

Why does this idea matter?

Why should taxpayers have to pick up the excessive security bills for people who are earning vast sums of money and then "hiding" these amounts in offshore accounts.